Home automation is a mess, IoT or not. There are standards like KNX, but the problem is the same as it was 30 years ago when the idea of home automation arose: manufacturers want captive markets and can't agree on a single standard. As a result, I can't buy any A/C unit, rolling shutter, light fixture and thermostat and just connect them to my home network, the selection of "smart" appliances is actually very limited.
I mean, home installation is thought out on the scale of decades, because renovation is a pain. People want something simple and reliable, that is the reason why some taps, switches, sockets, etc... are 10 times more expensive than others while looking the same and people still buy them. It is the complete opposite from what Silicon Valley is pushing.