I truely believe there is none. There is literally nothing people would pay for. We got ourselves into a situation where browsers have become so complex that they need an incredible amount of resources to get developed but the only way to get any money with them is to either sell the data of your users or have partners that do that (Google paying Mozilla for being the Firefox default search engine).

I literally don’t see a way out of this mess. In fact if Chrome needs to be split off from google, google has no need to keep Firefox alive anymore. If they just stop paying for the search engine default, Mozilla loses 75% of their revenue.