Endgame should and needs to be redefined to more than just current tier or cutting edge content.
But that is literally what endgame is, LOL. It's not called "side game" or "mid game."

You mentioned GW2, which actually in the past few years implemented endgame raids because its lack of real endgame was so heavily criticized. GW2's "endgame" was basically a bunch of leveling systems with some free-for-all raids that were chaotic and not much fun. (Hence the implementation of more traditional raids.)

Look... I'm not a hardcore raider. I barely run savage (haven't in months), and haven't even touched the most recent Ex primals. (My midcore static fell apart months ago.) But let's be real and not dance around what endgame in FFXIV is or isn't.

We don't know everything about blu yet. I don't believe it's been confirmed that Blu can't raid with premades... so maybe, with the right configurations, Blu will have a place at the endgame table. For now, though, all we really know is Blu is designed for leveling in old areas and participating in a high-level minigame which seems to do nothing to progress the job any closer to endgame activities.

It is what it is. Don't hate on me for that.