Aren't some ISPs and MVNOs already doing this though? Like Republic Wireless, Project Fi, Comcast's mobile service, etc. They eagerly prefer WiFi hotspots and

Aren't some ISPs and MVNOs already doing this though? Like Republic Wireless, Project Fi, Comcast's mobile service, etc. They eagerly prefer WiFi hotspots and give you access to a network of them with a cellular network in place as a fallback.