This architectural shift eliminates the user’s ability to expand memory capacity as self-hosting demands grow, effectively putting a permanent ceiling on running memory-heavy Docker containers, ZFS pools, or virtual machines.
That's not a NAS anymore, that's a full server. I think of a NAS as "low-power computer with lots of storage attached", so not being able to upgrade the RAM on one isn't all that surprising.
For business it should be all storage. But for home use the best is all-in-one. A home user doesn’t benefit from specialization of equipment, just brings them more headaches managing more stuff. One device that has storage and can also run Plex, Immich, HA in a single package makes the lives much easier for those who have to take care of the IT in the house especially of they’re not “IT people”.
Well that's just for home use. Say a small to medium enterprise needing a shared drive. Or even things like say video editing you might need a 10G connection. Furthermore for most it's just a hobby so there's no right or wrong, if you can live with the noise and power of old enterprise gear then kudos to you, or if you think a raspberry pi with a sata hat works then go ahead