Every six months or so somebody asks about the Community Satellite program. But it’s not easy to run your own and/or can be expensive to make it reliable… so it never goes anywhere.
The closest I think we get are those SNOs that share enough used-space: that with the regular bonus (and maybe L2 too) they cover their own S3 use. So are kinda sorta donating their unused local space to get “free” Cloud Storage. Clever!