Micron killed Crucial because Crucial was a weird offering that competed with their own partners. This was always a weird problem, and it just didn't make financial sense to continue with it. One of the analyses I read was Crucial was less than 12% of sales.
Like, don't get me wrong, I've liked many Crucial products over the years, and even recommended some of them, but it was always weird they were trying to out-compete companies like Adata and other major ODMs.
The counterexample of this is Nvidia absolutely trying to kill their partners, and going to first party assembly and sales of products. Nvidia isn't even going to PNY anymore for ODM needs, but going directly to Foxconn.
Micron execs claiming its because of AI is a bit weird and revisionist, because they've been working on exiting the Crucial brand since long before they publicly announced it. The public didn't learn of any such plans until right before the Ballistix brand sunsetting was announced in 2021, but started years before that. Like, I know they're just playing to their shareholders, but its still a bit weird.