This is so true. As someone who worked at a company that did power monitioring and wanted to (and did) expand into thermostat control.

1) Reliable internet isn't everywhere, it cuts out a bit.

2) A lot of internet enabled thermostats are just not that great at reconnecting when the eventually loose their connection.

Though to be fair the thermostats generally will just continue on the normal schedule if they loose connectivity.

The company ended up using on a different wireless protocol to talk from the base station to the thermostats. (z-wave or zigbee fwiw).

Ironically we had a 80s error programmable thermostat in the office, which worked pretty well.