How silly, of course they do. To prove a point I just called Leupold and asked the difference between a VX-1 and a VX-2. I was told the VX-2 has "better quality glass" and a "more robust and precise erector system".
I prefer Leupold scopes over Nikon but it has nothing to do with Leupold holding up better. I see better through Leupold. I also know people who see better through Nikon. It has to do with the way each company specifies the glass to be ground and the coatings each company specifies. And since everyone's eyes are different they will see better through different brands of scopes than others. Within Nikon I see better through the original Buckmaster than I do a Monarch even though the Monarch has more expensive glass.
Again, you're confusing features with quality. What Leupold etc. do not do is put lipstick on a pig.
For example, I have two old scopes, one from the 30s and one from the 60s or 70s. Actually 3 if you count the PU scope. By today's standards they're pretty much featureless. The glass isn't as clear as it could be by today's standards, the field of view isn't great, and they're fixed power. But they're every bit as serviceable today as they were when they were new, despite heavy use, and I daresay abuse. The adjustments are all intact, they hold zero, etc. They lack features, but the quality is still 100%.
With people like Bushnell and Vortex you never know exactly what you're paying for, and I would tentatively put Nikon in that group as well just based on their prices (you can't make a good scope for $100 any more than you can put 10 gallons into a five gallon bucket). Maybe the glass is great at the expense of quality control, or using substandard materials in other areas. Or maybe you get turrets, parallax, illumination, and a large mag range all in a $300 scope but all of it's total junk and won't stand up to normal use, if it even works right in the first place. And what I've found about those types of companies is they get so good at cutting corners that they do it everywhere to increase profit margins. You can't trust them to make a basic 3-9x deer scope without cutting corners and keeping the price the same as their higher quality competition. You think you're getting their premium product, but what people don't realize is that it's hard for companies like that to keep their corner cutting habit from creeping into their premium products.
BTW, you can
always get better glass. You can spend four grand on a S&B, but that doesn't mean it's necessarily better quality than a cheaper alternative.
There are also pros and cons to different erector assemblies, mostly in weight. If you have a very hard recoiling magnum then you have to go to the extra expense and weight to get an overbuilt erector assembly.
Precision and tracking are also tradeoffs. Someone shooting a deer at 50-300 yards doesn't need 100% tracking or adjustment precision (they're going to hold over instead of adjusting turrets anyways). Someone trying to make precise shots at 1k yards does, especially if they're adjusting their turrets on the fly, in which case the adjustments have to match the calculations exactly.