But I agree that's the catch - it doesn't make sense to throw money at open source models in hopes of direct return, so you need a nation or conglomerate to do it so as to control the technology they rely on.
elasticsearch the first example that comes to mind. you can run it yourself but elastic gives you so many lessons learned and tunes ootb that it sings with relatively little effort, though still reqiures some.
about a million dbs i could make the same comparison for