I have a (mostly) DYI smart-home, I mean, DYI as in "a Frankenstein of vendors and devices glued together by Zigbee, MQTT and Home Assistant", with some hard-deps on it in a couple of rooms and that gave me some bad nights when thinking about "what if I sell the home one day?" but reading the threads here I feel reassured: they will probably just rip it away and put some low-tech solution and call it a day.