Oh, it's a great argument. One of the biggest shifts in how D&D played at tables was the addition of easy item creation rules. They allowed players to sell off stuff they didn't want and basically convert them into the items they wanted. And what they wanted were the Big 6 (weapon, armor, prime stat boost, ring of protection, cloak of resistance, amulet of natural armor) because they were a lot more useful all the time than the more conditional but far more interesting items like the ring of shooting stars. That's the kind of item people were getting rid of by selling them and picking up the Big 6. The 3e/4e versions of the game made that kind of thing so easy to do that the way the game played really shifted. 5e's take on magic items helps shift it back and it's one of the reasons I like it as much as I do.
And I think your calculus on items with more pluses being worth more is way off. Thanks to bounded accuracy, +1 is QUITE sufficient. In fact, the main reason I want it as a player is to cut through most damage resistance more efficiently and a higher plus doesn't really help me do that. But you know what? Even without a magic weapon, I can STILL hit monsters and kill them, it just takes longer. So that's even an improvement over AD&D days.
