You have a completely different perspective on what is expensive is the problem. For the vast, vast majority of people the idea of dumping 2k+ in to just a land base of duals for legacy is completely untenable.
I'm not assuming any casual player is going to jump right into legacy, or even your typical FNMer. However, for a serious standard player it doesn't take long for standard to become more expensive given the demand for new cards is fickle, and prices never stick.
Look at last rotation with 4 color company and $80 Jaces. You had a tier 1 standard deck that was approaching modern prices, much of it on the back of a single mythic rare you just happened to need 4 of in every significant deck at the time. So it's a choice, you can dump $320 on a playset of flip Jace and play standard, or you could take that $320 and buy duals. All the duals in Maverick cost less than $320 combined, for example. It buys you an absolutely pristine Underground Sea with a bit left over, or two played Tundras.
Six months from now, those Tundras or Seas are still worth what you paid, and standard has moved on. That money has evaporated. Cracking boxes is even worse. I bet we all know standard players who buy a box, maybe even two or three, of every set. That's every 3 months they're throwing money at the wall, and unless they've got an out for all that cardboard it'll sit and lose value. Add it all up, and the hidden cost of standard is quite high with few chances to recoup the loss without a storefront.
I readily acknowledge that my perspective differs, but it's not one I came to in a vacuum. I scraped my way into everything I've got just like everyone else, and I never dropped huge sums on anything but power (and as i explained earlier in the thread, only a fraction of the total cost was actual cash). If you really want to be playing Magic in 5 years, it makes more sense to buy a dual land that will always have value for as long as the game exists than a standard card that will spike for a couple months, and maybe retain half that value when it rotates if you're lucky. Most standard staples retain much less.