Home assistant is great at what it does, but the problem is too big for HA to really fix it by itself.

It's the end-devices that are the biggest culprits, paired with the apps installed on your phone. It's the reason Google was basically giving away their home-mini's the last couple years.

If you use a smart device that comes with - or requires - an app, it's almost guaranteed that app collects a certain amount of data from you to be sold or utilized for user profiling.

The problem is that everyone has half a dozen of those devices already, and swapping them all out takes time, effort, and money that most people simply don't have.

It's a challenge even for the truly dedicated and privacy-minded individual to know which devices are locally hosted and which ones use local internet access or a permissive phone apps to function. Even if you DO manage to keep a clean slate, there are always companies that change their policies once they have high-adoption and force cloud integration on their users. See Phillips, Chamberlain, Microsoft, Google, Amazon...

I love Home Assistant, but it's a nightmare trying to cut out all the unsecured bullshit I've found myself with even in the past two years.