The issue with this is that inevitably the locked down devices, which will end up being 98%+ of the market, become required for ordinary living, because no-one will develop for the 2%.
Open hardware is essentially useless if I need to carry both an open phone and a phone with the parking app, the banking app, messenger app to contact friends, etc.
For security reasons it makes sense for them to be different devices. People and services may not want to allow insecure devices to communicate with them.