Because the market demand is small and the profit margins narrow or nonexistent.
I mean a lot / most open source software has always been free and resistant of spyware, but has e.g. desktop linux ever taken off outside of a relatively small community?
There ARE companies capitalizing on the demand; they're frequently mentioned on HN, companies like Proton/Fastmail, chat apps like Signal, Matrix, etc. All of cryptocurrency, a software and financial product that was / is intended as a privacy tool (like cash money), is a global $1 trillion market (according to https://coinmarketcap.com/), with most clients and protocols being open source. (maybe I'm reaching here)
I realize the FSF itself, being a foundation, isn't the correct answer (been a member for years) but a related for-"profit" outfit, run ethically, seems only a modicum of management talent out of reach.
The main issue is that privacy and tracking are a death-by-a-thousand-cuts type of problem. Whatsapp may be tracking me, so I'll switch to Signal. But then I have to worry about Twitter and switch to Mastodon. Then I have to worry about a long tail of apps (notetakers, camera apps, flashlights, etc.) and find/build replacements for each of those. And even after I am done with the app-level tracking (if ever done), I still need to worry about OS-level tracking (at least in Android/Google Play Services/...).
Those thousand cuts drain into a data lake. There, even reasonably sane security policies on discrete sites can be substantially mooted by combining a bunch of data from disparate sources.
I mean a lot / most open source software has always been free and resistant of spyware, but has e.g. desktop linux ever taken off outside of a relatively small community?
There ARE companies capitalizing on the demand; they're frequently mentioned on HN, companies like Proton/Fastmail, chat apps like Signal, Matrix, etc. All of cryptocurrency, a software and financial product that was / is intended as a privacy tool (like cash money), is a global $1 trillion market (according to https://coinmarketcap.com/), with most clients and protocols being open source. (maybe I'm reaching here)