Community approach basically failed in building a "web of trust" with all the PGP/GPG signing parties: both tools were tricky to use, integrating PGP/GPG signing into common tools (like email, word processors, web, but also version control systems like CVS, SVN, bzr, git...) was always lackluster.

LetsEncrypt is a surprising success, but it's still a centralized system running as a non-profit — which means that it's always at risk of not being funded and/or to be under influence of big sponsors. It also came too late, app stores were already centralized.

Obviously, enterprises prefer to be the one to gate the access, so with a situation as it was, they jumped on the opportunity.