Because the market is actually pretty small for expensive thermostats. I bought the original version of the Nest thermostat because I wanted to remotely control it via my phone. Most of the smart features are horrible, the AI is dumb, and the fact that controlling it depends on a server that may be EOL'd scares me.

Most thermostats are in the neighborhood of $25-$50, so $250 for a thermostat that offers marginal utility is a hard sell.