If google were going out of business I'd agree with you, but they're not. As a business they have plenty of money. What they're (possibly) doing is shutting this service to save some money. I suspect they'll refund or at least credit the relatively small number of people who purchased games on the service.

It was always an odd setup to sell something for a fixed fee that potentially has an endless cost to deliver. Google have always been vague about how to square that circle. They could have sold fixed term or rolling licences but chose not to. I suspect had Stadia game sales reached a certain threshold they'd have done something like that but it's not something you want to talk about with a new system.