I looked through the different sites, and while they look good for standard games, they are “too optimized” for next-gen gaming. From the looks of the different buildings and characters, it looks like they use a mix of bump mapping and normal mapping, which is great on a monitor, but not in VR - which means that almost all of these assets are non-usable without heavy modification, which at that point, it wouldn’t make sense to purchase it since I would spend more time fixing the models than if I had just done the work myself.
However, may not be the case for you… every game, every studio, has their own specific needs when it comes down to it.
I hate to be the one to say , as I respect the time and effort that it takes to put something out there (I am a modeller as well), however, content producers need to step up their game and start using a mix of normal maps for the extremely small details, and tessellation for the bigger details.