Your apt update would still be huge though. When the dependency changes (eg. a security update) you’d be downloading rebuilds of 20 apps. For the update of a key library, you’d be downloading your entire distribution again. Every time.
Oh, well yeah, statically linked binaries have that downside. I guess I don't think that's a big deal, but I could maybe imagine on some devices that are heavily constrained that it could be? IDK. Compression is insanely effective.
NixOS "suffers" from this. It's really not that bad if you have solid bandwidth. For me it's more than worth the trade off. With a solid connection a major upgrade is still just a couple minutes.