A theory: in the 0e-1e-early 2e days, magic was "extra". Most PCs and nearly all NPCs would be non-casters, or at least non-mages. Perhaps more important, those characters who
could cast couldn't do it very often, until high level anyway. Casting was also less reliable, and easier to interrupt, and some spells (e.g. Teleport, Poly Other) carried serious risk for either the caster or the target. Magic items were common, but as they could be destroyed fairly easily they were seen as only being important while you had them. And as no DM could ever know what items her party would have at any given time, magic items weren't built in to the math of the game other than magic weapons being required to hit some creatures. That said, when it did work magic was often special and sometimes spectacular.
Then came 3e, with item creation for all made easy and (relatively) cheap, along with a much greater number of classes and PrCs that could cast, or quasi-cast. Items also became much harder to destroy; and were built in to the game's math expectations. Bards became mostly-full casters that could start at 1st level, rather than Fighter-Thieves with something extra tacked on. But there were still some hard limits on how many spells anyone could cast in a day.
With 4e, item destruction went away completely and a few classes were given always-on casting. Some classes that would normally have been non-casters were given quasi-magical abilities. Also, by now any serious risk associated with casting is gone; and casting is much harder to interrupt.
And now there's 5e, where items have decreased in importance somewhat but casting has gone nuts. Casters can cast something every round, all day long if they want to. A far smaller fraction of the classes are fully non-casters, when compared with 0e-1e. Which means, in comparison to 0e-1e everyone can cast now - you get and spell, and you get a spell, and you...etc.
End result: magic has gone from being extra to being expected; and thus from exciting to ho-hum.
Answers there are, but we can get to those later.