There is a nice video out there that claims it is impossible. I was blissfully unaware of it, but a friend of mine sent me the link, presumable because the video references me, however briefly.
I went and watched it. It really like the production quality and he really gets a lot of the details correctly (though not all). There is, however, one absolutely glaring error and a few minor ones. Now, that alone would not make me want to make what is essentially going to be a rebuttal video. I decided to sit down and write down my thoughts before I make the video. Than I decided to share these thoughts with you in a written form before I get to the video itself.
I do not like doing these critique jobs. However, he is doing a pretty shameless straw man argument, so I figured it is worth my time. I do not think his intent is malicious, but contrarian arguments get a lot of clicks. It is very fashionable these days to find a product that shows up in serches a lto and crap all over it to make yourself stand out. Still, I am going treat this as an error, rather than an attempt to obfuscate. The single biggest error and the one on which his whole argument hinges on, is that of expectations. He never states it out right, so noone really catches onto what is essentially a slight of hand.
There is a lot of footage of him walking up and down rocky hills with lots of nice gear and interspersed with diagrams only marginally related to the subject discussed. It all looks authoritative and sounds really awesome. If you follow the logic of his argument it all really makes a lot of sense. If you accept his underlying assumption that is. The assumption that is never quite stated outrightm soit does not get challenged.
If you assume that a 1-10x LPVO is supposed to supersede BOTH lower mag ratio LPVOs AND Larger objective 2-10×40 MPVOs scopes, it all makes total sense. However, that is not what they are for. They were never intended to peplace larger objective designs specifically for the reasons stated in the video: exit pupil gets small on high magnification when you have a small objective.
1-10x scopes are intended to extend the capability of lower erector ratio LPVOs in a pinch, not to supplant larger scopes.
A 1- 10x scope is indeed harder to build than a 1-4x, 1-6x or a 1- 8x. That's why good ones are expensive. Somewhere in there he insinuated that he'd like a SFP 1-10x scope and they do exist, but there is a good reason to make these with FFP reticles when you consider the general purpose application. Honestly, a part of his argument almost seems to be "they do not make these in the configuraiton that I'd like, which means it is not possible to make a good one". That's a flawed argument at best.
Even with 1-8x designs, the trend is clearly toward FFP scopes and, again, for a good reason. One of the many reasons to go with a FFP LPVO is that the reticle works on all magnifications. MOst importantly, the reticle is designed to do different things on different magnifications. That is intentional. While a significant number of people do only use them on the lowest and highest magnifications, the biggest reason to have an LPVO on your AR is to be prepared for situations you did not expect. That's where the flexibility comes in. Another benefit of FFP designs is that in a modern LPVO you WANT a sophisticated free reticle on 5x and above to use for trajectory and wind compensation. However, on Ix you want it to look like a simple reticle: bright dot, #4, etc. You do not want to see the entire tree. That is not possible with a SFP only design. With FFP, it is easy to set things up so that all the busy stuff disappears out of view on low magnifications.
Now the criticism that most reticles in current FFP LPVOs are not sufficiently visible on lx without illumination and reticle illumination does not have a particularly long battery life is generally accurate, but not entirely valid. First of all, it is absolutely possible to design a reticle that works fine in FFP LPVOs on 1x. However, several companies deliberately do not do that. They choose to have the reticle disappear on 1x, so that all you get is a bright dot. A good example't that is what is arguably the most sophisticated tactical LPVO on the market at the moment: S&B Dual CC 1-8×24 That happens to be a dual focal plane design, but the idea is the same. Steiner's new dual focal plane version of the M8Xi is set up in a similar way as well. Razor Geis 1-10×24 is FFP only and while the reticle has some visibility on 1x, it is not a ton without illumination. The reticle can be easily modified to rectify that should they choose to. March, with their dual focal plane 1-10×24, did exactly that. FFP reticle becomes very unobtrusive on low power, while the SFP reticle remains of the same apparent size. Essentially, it is a tree reticle on higher magnifications and a simple # 4 reticle on lower magnifications. The ACSS reticle in PA's 1-8×24 PLxC is FFP only, but it is set up to work just fine on 1x non-illuminated. It would work in exactly the same way in 1-10x as it does in a 1-8x.
Then there is an argument that in 1-10x scopes the performance on 1x is not good, with Razor Gen 3 1-10x shown as an example. He even has the camera show you a picture through the scope.
This is the part where I can't tell if it is incompetence on malfeasance.
1-10x scope is clearly not focused for the camera, while the other scopes are. If I were trying to sabotage how a particular scope looks, this is how I would do it. Now, I have seen a couple of other Youtubers make the same claim about the Razor and the pictures show the same thing: they either did not know how to set the scope up or intentionally set it up to look bad. Vortex bashing seems to be popular these days and is good for clicks. Perhaps it is as simple as that.
Ultimately, the moral of this story is pretty simple: FFP 1- 10x scopes are not simple to build, but it is clearly not impossible. When discussing a scope, it is a good practice to understand what it was intended for. Otherwise you end up with a straw man argument.
Oh, and when someone claims to have taken "engineering physics six hours a day, that usually though not always means that a sociology major is trying to impress an english major. "Engineering physics" is a class for social studies people who need to fulfill a science requirement to graduate.
For background, I own two Razor Gen3 1-10x24 scopes, so I have spent a lot of time with them and have seen many more of these at Vortex' facility. I have spent a LOT of time with two March 1-10x24 dual focal plance scopes. I own two Primary Arms PLxC 1-8x24 scopes and March Shorty 1-8x24. SAI 1-6x24 is here. Tract 1-8x24, Steiner P4Xi 1-4x24 and PA Slx 1-6x24 are as well. I bet there are several more I can not recall right offhand and that does not include a good number of various prototypes. I have lost count of how many LPVOs of all possible flavors have gone through my hands over the years. I was there essentially for the entirety of their evolution as general purpose AR scopes. I have provided feedback and consulted on a good number of them. Quite a few of the companies I provided feedback to did not necessarily follow my recommendations. That does not mean they made a shitty scope. That just means they prioritized something differently from the way I would, or had a somewhat different dsign goal or simply chose to go witht he feedback of a different SME. There are a few of us around and we do not always agree with each other. Design goals matter and they might not coincide perfectly with what you are looking.
It is slow, but accurate and consistent.
This ammo showed some mild pressure signs, but not too significant. 
