yes it is a bit of everything.
materials, how precisely the lens is ground, coatings (anti fog, UV protection), the ability to change lenses (and the locking mechanism for doing so), etc.
again, since i am into APEL and military certified eyewear, i typically stick to clear and black lenses as polarized, transitions etc are not allowed
but aside from that issue, brands like Pilla make special lens colour coatings for every application you can think of, e.g. make skeet shooting clays "pop", make red dot sights appear brighter, make archery targets appear brighter etc.
one of my more interesting shades are the Spy General with their "Happy Lens" technology that minimizes harmful blue light but enhances "good" blue light and that is supposed to put you in a better mood. Not sure if that is the case but they sure are nice to look through.
As for your specific examples, i recently got ESS Flight Deck goggles and they were the clearest clear lens i have ever seen. i actually said "wow that's clear" when i put them on. I wouldnt say SMITH and Revision are especially nice to look through but it is nice to have the confidence of their protection.
RL