Yeah, I get what you’re saying. Definitely. It’s not complicated for one pair of speakers in one room. For one music source. For one person controlling it.
There just haven’t been any better cost-effective solutions with multi-room, control from your any phone convenience. And that’s a big plus for how we listen to music. Today there are a few contenders, but many of them are also cloud dependent. Really the small number of good options in this space is proof of how good Sonos was for a long time. Well and also of Spotify causing people ditch the idea of a offline digital music library.
Edit: And to be clear, aside from the “any computer networks” part, this is what the original Sonos device did. It could work without a home network, but worked best with a shared music library on a PC. Didn’t need cloud anything, internet connection, account, etc. You just hooked your normal speakers to it and it played music.