The current email protocols can’t be easily encrypted. There are multiple providers and clients that are not compatible, you often have to put people in copy that don’t have public keys, or get replies in plaintext, you may want the content accessible to different people for documentation or legal purposes, some functionality will be broken or become hard to use, it’s asynchronous, and there is simply little demand for privacy from the providers.
The use cases are currently niche, in places like dark web.
In short, “if you have nothing to hide, you have nothing to fear.” I disagree. Privacy is a fundamental human right essential to a functioning democracy.
The use cases are currently niche, in places like dark web.