By "almost nobody", you mean everyone who used Apple Mail/GPGTools and Thunderbird/Enigma, meaning, the vast majority of everybody who used PGP?
I don't know anybody who is using Apple Mail with GPG, but if there are such people, they have been doing it very wrong regardless of this vulnerability. It's an unsafe combination.
I have no statistics on what people use PGP with, but asserting that most people use it with Apple Mail and Thunderbird is baseless and without proof.
The researchers behind EFAIL found a number of ways to bypass the remote content setting. Not only that, but Hanno Böck found another one today[1] that hasn't been fixed yet.