One startup idea I briefly pursued some years ago was developing privacy focused work-alikes for common utility apps, and what I sensed from it was after "flashlight," "calendar" and "QR code reader" apps are their own contained brand experiences. There is no messenger workalike, each game is itself the experience, and playing a clone is less satisfying, and there's a quality to apps that is as intrinsic and unique as a story that you can't just replicate.
The business model was to charge for privacy focused work-alikes of popular free utility apps as an effective luxury privacy brand for apps, but even this misunderstood luxury products (an area I had some experience with, in addition to security and privacy). Luxury goods represent stories of aspiration and belonging, where privacy is a reactionary value that needs a foundation of something valuable beneath or behind it to protect. It's a quality and a feature, but to succeed, it can't be the reason.
To be valuable, privacy needs to socially elevate the user, similar to how the whole apple brand experience does, and distinct from the way someone using Tor/Tails all the time would relate to the world. Privacy as a concept has acquired the vibe of an inferior good, something you want when you don't have power, and so it's not something used for elite signalling the way exclusivity was just 20 years ago.
In this sense, privacy must be attractive, which is a real magic sauce. To do that, what people mean when they say something is cool or sexy is that it is powerful. Together, it means that for a privacy centric tech to succeed, it must first be powerful. Blockchains and cryptocurrencies were technically powerful, but their bar to entry meant they were adopted by unpowerful people first, and are still percieved as an economic "inferior good." Power over things is just leverage, where desirable power is necessarily status over other people. There's a lot of opportunity to refine this still.