This isn't an awful deal for either side. Garrett will be 31 and has cap hits north of $55MM scheduled for his league age 34 and 35 seasons. Maybe he'll be a freak of nature like Julius Peppers into his mid- to late-30s, but it's far from a guarantee. Meanwhile, Verse is very unlikely to ever be a player of Garrett's caliber, but he's a very good player already and only 25.
This is the ultimate all-in move for the Rams, who have one, maybe two years left with all their chips. And it's knowing what you have for the Browns, who are still at least a year or two from contention, even if one of their several young QBs works out.
I'm not upset we won't see the Rams until at least the playoffs though.