>They've definitely slowed, but they haven't stopped.

Yes if you span into 40 years. But the spot price for DRAM floor was ~$2/GB in 2008 and touched that 2-3 times over the next 15 year. It wasn't until early 2020s it broke that into $1.

Process shrinks happen but majority of DRAM part can't be shrinked by process any more.