I think it has more to do with the 'common wisdom' dictating that this is the way to do it, as 'we've always done it like this'.

Which might even be true, since cloud based software might offer conveniences that local substitutes don't.

However this is not an inherent property of cloud software, its just some effort needs to go into a local alternative.

That's why I mentioned Home Assistant - a couple years ago, smart home stuff was all the rage, and not only was it expensive, the backend ran in the cloud, and you usually paid a subscription for it.

Nowadays, you can buy a local Home Assistant hub (or make one using a Pi) and have all your stuff only connect to a local server.

The same is true for routers, NAS, media sharing and streaming to TV etc. You do need to get technical a bit, but you don't need to do anything you couldn't figure out by following a 20 minute Youtube video.