Looks to my 1048-page, 4-volume set of the 2e Wizard spell compendium, filled with hundreds of spells that maybe one player ever has cast once.
I mean, sure. If you want magic to be able to solve any problem, that is a thing you can do. But why have spells? Just replace every spell with Wish?
Now that's a hyperbolic statement, and if I was serious, I'd feel bad for even typing it. I don't think that's what you want. Likely, you think it makes sense for the world to be full of many thousands of spells, as it makes the setting seem more real, and it adds to the lore of the setting. Interesting spells can be sought after or found by players and even if they aren't particularly useful in adventuring, not all wizards are adventurers. So perhaps someone does have a spell that, say, conjures a comfortable easy chair out of thin air so the caster always has a good place to rest their aching bones.
But do these sorts of spells need to be in the Player's Handbook? Should they be offered to players who are expected to be adventurers as equivalent options to things that do impact what they are expected to be using?
And of course, can the game or it's setting handle all these applications of magic? Is it ok to think about a group of Wizards starting an industrial revolution by conjuring walls of iron and using fabricate? Or making a dozen simulacrums of craftsmen for their assembly lines?
Should a DM have to worry about ever giving Wizards downtime for fear of what they could do with their spell slots when there isn't an impending apocalypse or deadly trek into the wilderness?
Would the resulting world even look like the "classic" D&D setting? If magic can, in fact, do everything, would Wizards become a ruling class of elites and everyone who doesn't have magic be considered a second-class citizen?
Or would the people rise up, overthrow the Wizards, and outlaw their craft, all but ensuring their removal as a viable player option?
While unlimited magic can be great fun for a story, I don't know that it's great fun for a game where not everyone is expected to be a magician.