I’ll pay. So what are my options? What paid, ad-free social network is there that most of my contacts are on?

There isn’t one. LinkedIn is sort of an exception but it’s not for general use. The market isn’t providing s supply of these products so I don’t see how you can say there’s no demand. New social networks have such high barriers to entry that you can’t just point at some random failed paid one as an example. Loads of free ones fail too.

What would be interesting is if Facebook offered a paid, no data-mining option. But they do t seem interested in innovating.