signify[1] is approachable at least for the power users - I could print out that man page on a T-shirt. HTTPS is ubiquitous and easy, thanks to ACME & Let's Encrypt. E2EE with optional identity verification is offered in mainstream chat apps.
And of course there are usability improvements to GPG, being made by third parties: Debian introduced package verification a couple decades ago, Github does commit verification, etc. What's to stop e.g. Nautilus or Dolphin from introducing similar features?
I wonder why there aren't more, but there are some, for example Proton's efforts towards encrypted email.
https://proton.me/support/how-to-use-pgp
(I won't mention the relative shortcomings of HTTPS and E2E chat apps here.)