People asking some great questions in the notes of this one so I'm going to have a bash at them. First of all, yes, everyone else learns Endure first: they learn to protect themselves before they do Joker, to put on their own oxygen masks first. They also learn these skills at a lower level.
In case you need ideas for angstfic, Futaba has her own set of abilities and never learns either, so presumably she can always hightail it out of battle in her UFO as the only survivor.
Only Akechi learns Endure and Protect out of order. Only Akechi is more concerned about saving Joker than saving himself:
It's likely that says more about the value he places on his own life—after all, he doesn't learn these two until he's already behind the door—but let's just have a look at the descriptions of those two abilities:
Protect: Chance to shield Joker from an otherwise fatal attack.
Endure: Chance to withstand an otherwise fatal attack with 1 HP remaining.
Much has been made of the fact that Akechi-with-Endure appears in the true ending, while Akechi-without-Endure does not, so I won't belabour it here.
do we see akechi learn protect?
A few people are validly pointing out that he appears to learn both of these at the same time, and it does seem that way—but no, there is still an order, and it's deliberately been reversed from the order everyone else learns these two skills in—because of what he's doing.
Because I think we see Akechi learn Protect. Cognitive Akechi walks in, and Akechi turns to look at him along with the others—though he isn't shocked like they are. Akechi doesn't react until Cognitive Akechi turns to Joker and threatens him and the Phantom Thieves:
Notice that. Akechi is looking at Cogkechi like the others, until he issues his threat. And ONLY THEN does he look at Joker and go !.
It even gets a textbox, so we can't miss it. It's that important. And it's the same whether you have maxed his confidant or not. Because he's always going to sacrifice himself here—and he always did.
Game logic wise, he doesn't get the skill until rank 10, of course—the same point he learns Endure, after Joker reminds him of their rematch and gives him something to live for. But narratively? He's already behind that door. He's already made his choice. I think that moment he realises he's not prepared to let the others die matters.
Also, yes, Cogkechi's threat is explicitly and always to the whole group:
Cognitive Akechi
⋯お前らは、後だ。
... omaera wa, ato da
...I'll deal with the rest of you later.
This is really IMO more like "you guys are next". That omaera—"you and your group"—is aimed at Joker. Cogkechi turns to him, addresses him, then turns back to Akechi.
I reckon that's the moment things really crystallise for Akechi: Joker and the rest are not getting out of this alive if he doesn't act. People ascribe all kinds of motives to his sacrifice—he just doesn't want to live, he just thinks this is the best chance of his plan still coming off, and so on and so on. No. Watch this moment. P5 is a story about friendship and the bonds we make. That's what's going on here: the kid whose loneliness led him into evil finally has someone (or several someones), and he's about to die for them.
"he sacrificed his own life in order to save you". It's right there, look.
everyone else learns protect too though, right
Deaths in game combat seem to be a bit "you passed out and ran to a Pokemon Center". I'm pretty sure any and all of the kids would die for Joker and each other, if it came up; Ryuji has a damn good go at it, at the end of Shido's Palace. But Akechi's the one whose sacrifice is the climax of his story, the moment he's forced to decide what really matters to him, the things he's lived his life by or the person (or people) he's found—and in the original P5 and both P5R confidant tracks, he chooses well.