IF I lived in a smart home, all of that shit would be flashed with custom firmware from a github repo and all of it would be self hosted. The whole system would be capable of working as intended even if I cancelled service with my ISP (self hosted)

Also some things like access to the home via the door would not be dependent on power or battery. Those failure is unacceptable cases would have an analog backup (so a custom firmware flashed smart lock could still be unlocked with a key)

“The computer can be used as a tool to liberate and protect people, rather than to control them.” - Hal Finney, 1992

However, no company is out here giving users control. It's sort of something you have to seize for yourself.

And as far as the "What if it gets hacked" concern goes: Yes.

Have fun freaking yourself out: https://www.shodan.io/