Do you want to become a Billionaire? Make a privacy app so good that the government has to back-door acquire your company to break it.
"If I were a programmer today, I might think seriously about doing this. Learn state of the art crypto. Create a strong privacy app, end to end encryption. The strength is key to getting your company purchased by one of the big guys, you want to garner a strong reputation as a privacy app that no one, not even your company, can read the messages."
"Put it out there and watch the users roll in. Collect a hundred million users and watch the CIA begin sweating. The more times some criminal is using your app to sell marijuana and they realize your app is a black hole they can't penetrate, the more likely you are to get Microsoft's acquisition team knocking on your door some day with a billion dollar briefcase."