In Finland people have started since 2022 adapting their electricity use to shift their peak demand. But we started installing smart meters almost 20 years ago. I think the key reason to install them was less about consumer demand response, and more about saving physical visits to read the meters.
It takes some time to adapt (and also some quite extreme price fluctuation to motivate). Also good tools to automate demand response based on market prices were needed. Heat-pumps and EV chargers can now be configured to run on the cheapest hours etc.