Exactly--which is why most (but not all) more expensive 1" variables hold up better. But it's also why the variables most hunters buy, retailing for under $500 (often well under), aren't as tough as moderate-priced fixed scopes.
It's also the reason there are so many really tough 30mm-tubed variables. They can be reinforced in the right places, including the magnification-change tube, without the necessity of making everything thinner to fit inside a smaller space.
It's also far easier to make a low-magnification 1" variable tougher, the reason several people have cited the 1-4x and 1.5-5x Leupolds as being very reliable. Lighter parts aren't as subject to jarring during recoil.
