I still think a Forgotten Realms update is most likely for 2024 (at which point SCAG becomes "Legacy Content"), but since some Eberron options have yet to get the post-Tasha/MOTM treatment, I can't rule this out either.
Lots of them still know spells. But they are more of the control or support type then offensive spells.
They really won't have spell lists anymore. They have specific spells x/day and an at-will attack spell or two. They won't have fireball listed unless that's their go to at-will spell. Since they won't give at-will to their highest level spell, a caster that could theoretically cast fireball might only have burning hands as their at-will spell. Note this also prevents any upcasting too.
Well it is forgotten for a reason
Yeah, but so what? What WotC wants and what you want as a DM have nothing to do with each other. I mean heck, if WotC decided to stop having any NPCs and creatures wield longswords throughout all their books, does that mean every DM out there would have to stop including longswords too? That they couldn't create their own NPCs that wielded longswords? Of course not. The exact same reason that DMs right now can continue to use caster statblocks from the original MM if they really need their monsters to have spell slots and be "real spells" from "real spell lists" so that they can be assured they are counterspellable. Or that they can just treat these spell-effect features in the new statblocks as spells like they pretty much are, and let players counter them.
