Hopefully, someone will put them out of business with a decentralized system. They would sell standalone chargers that accept credit cards, and publish their busy/not-busy/broken status to some standard database.
Ideally, the database would be run by the government or nonprofit service. It would provide GPS coordinate based bounding box queries of each charger's status.
I think the whole US database would fit on a raspberry pi that's stuck behind a CDN (with a second raspberry pi elsewhere for disaster recovery).
Obviously, it would be run on something slightly beefier, but I can't imagine the server costs exceeding a few thousand a month.