10% of "all" created stuff is a very high estimate!
Yeah, Not sure I would spend the money on that asset just for myself but at least you save $50 on not needing the distribution licence for it that way, so $25 is more of a reasonable cost for a personal project.
I expect a lot of personal projects turn to less than legal means to get their assets too, but you can't upload those on the hub then! So no point talking about that. If he can't convert the asset himself he would need somebody else to turn the models into an assetbundle. If it's not from a legal source, that itself becomes an issue.
My top tip for anybody wanting specific models that are hard to find or expensive is "Blender is free, get it and learn it.", build your own models! (I know, it's hard and not everybody has the talent, but it's certainly worth a try.).
I built a complete replica of my main VR room including all fixtures and fittings accurate to a +/-2cm. I can walk around in VR in it and know where things are! It's fun to bring a VaM model into your own "real" room. That will never get distributed and took a lot of effort to make but it was a fun project and worthwhile I think.
I am rambling, sorry.