Well that was the sticking point when all of this first happened, a bunch of publishers instructed Nvidia to remove their games from the service. They felt they were entitled to further fees (or to sell the games again but with cloud permissions) for whatever reason despite the fact that customers who want to use GFN already own the licences for the games they want to play. For customers looking to use services like this they just want to play the games they own digitally on PC via a powerful cloud PC.
Thankfully many publishers/developers have since realised how ridiculous/greedy they were being. If a person is primarily going to use GFN or a similar cloud solution rather than local hardware then the publishers who have decided to withdraw themselves lose out entirely - the person likely doesn't buy the game at all in this situation where they are being restricted.
The sticking point here is especially with publishers who have their own cloud solution for their games. They don't want people buying their games elsewhere (GFN is compatible with pretty much all PC storefronts with the exception of Microsoft and Activision's storefronts) and then using a 3rd party's streaming service when they have the opportunity to funnel people towards buying on their own storefront and using their own streaming service. In that situation it of course means less freedom for the customer (GFN might be a better solution than Xcloud for example dependant on the users location and Internet capability, or even just due to the fact that GFN's PC's are very powerful) but they don't care, it's about exercising control where they can.
I believe the situation is now one where Nvidia just reach out to publishers/developers regarding games on an individual basis to get permission for owners to be able to use GFN to play those games. I've not seen anything conclusive to suggest Nvidia offers revenue sharing deals to anyone, it wouldn't make sense for them to do so, especially now there are just a couple of holdouts.
It's a shame that some publishers are refusing to come to an agreement with Nvidia but at the end of the day they are just making decisions that they believe are best for their own businesses. But from a users perspective if you own a PC version of a game you should be free to play that on any hardware you want to, even if said hardware happens to be a rented PC on the cloud.