Thats easy: service providers can train on the spftware to offer the service. Its literally what theyre for. Redhat didnt make linux but charges a reasonable price to support it. Like lets open source slack or something, and enterprises could self host it, or get it served by one of the service providers that pop up. And if there are bugs that are reported, then the service provider could use AI to fix them and upstream the changes so all the users benefit from it

The difference will be that they can have rent seeking practices when the software itself cant be taken hostage. They'll charge for the service and wont leech off the user for way more money than they deserve for making and maintaining the software