There are ways around this. I quite like what TimescaleDB have done, with most features OSS, and the more advanced features are under an open source license that permits use for those building a product around it, but preventing TimescaleDB as a service.
Agreed, but I think there would be big pushback from OSS proponents - in theory changes like this are diametrically opposed to the "No Discrimination Against Fields of Endeavor" tenent.
The problem of big cloud providers ripping off OSS works is a new one, but it is explicitly allowed by OSS licenses - really not sure what a "good" solution is here, but personally I like the route TimescaleDB has gone down.
I don't think it is a new problem, there have been people offering Apache servers as a service for a long time. Same for PHP, Wordpress and myriad other open source projects.
TimescaleDB's TSL license is not "OSS", but it is open source.
TimescaleDB has a good blog post about why they went this route[0]
I do think that perhaps we need to stop being so snooty about OSS vs open source, and recognise that companies with open source products are allowed to make a profit while preventing the big cloud providers from scalping them.