I still hope Dominaria has Masterpieces.
Especially since it's a single set and only needs to hit 30ish options rather than 50+, I am 100% confident Dominaria will have Masterpieces. The only question is how heavily the frame is influenced by the classic one.
throw in some expensive lands, that always works
The thing is, they already pretty much fixed the problem with expensive lands. Back in the day with 121 rare sets it was pretty easy for important lands to go for $30+ since they were hard to pull from packs but still vital for Standard. These days the phenomenon is much rarer (so to speak) since they're always at the rare slot so their total value is limited -- even the fetchlands got down to $12-ish in Standard. Because land cycles represent 5 cards they're also good at splitting up value across the set.
So card prices lowering turned out to be a bad thing in the end?
The problem is it's a balancing act. Boosters cost a certain amount to buy, and the average value inside will always converge on that price from above. If that average value is heavily tied up in super-rare expensive cards, the median pack will have pretty bad value, which disadvantages booster buyers and drafters against large dealers who can open enough product to overcome the median, and fucks up the prize economy since there isn't a good way to reward people in tournaments outside of product.
The thing is that it's also bad if the median pack value is out of whack because of regular expansion cards (this is why i disagree with kirblar's Baneslayer example)
or if Standard decks go way over the average to build from parts (ideally Standard decks should be in the $150 - $300 range; when you get $500+ prices on top decks it tanks participation.) Masterpieces were supposed to avoid the latter but they wind up being too much like the former.
The thing is that the actual best solution to this (other than lowering prices which isn't feasible for a wide variety of reasons) is a thing that Magic players vocally complain about endlessly: put a bunch of different staple cards at Rare so median pack value is closer to average and therefore any
given staple isn't that far out of whack. This is why good rare land cycles are useful (they soak up a lot of value on broadly playable cards) and why better sets from this perspective are often ones with very usable rare cycles.