Edit: How is the end game content nowadays? I remember hearing it was fairly weak.
When people talk "endgame", they usually talk about "carrot to chase".
In World of Warcraft, this was the endgame:
10: Run the same dungeons over and over to get slightly better gear. GOTO 20
20: Run the same raids over and over to get slightly better gear. GOTO 20
The only "break" from this cycle was either: when an xpac came out with new dungeons and raid, and then the cycle began anew, or you focused on doing dailies instead, which involved running around the same zone over and over doing the same quests, every day.
Or, go do the things mentioned in the rather expansive list of achievements, like world completion, collecting things, etc.
Or grinding for rep. Or making an alt.
And people loved that, and consider that the "best endgame in the MMO genre".
Now I'm not saying it is, or isn't. I'm retired from WoW, so I did all that stuff plenty.
In Guild Wars 2, this is the endgame:
Run the same dungeons over and over to get gear that has a look you want.
Run the Fractals over and over for rewards, and to get gear that has the look you want.
Do the new story content that comes out every two weeks.
Do the new zone-wide content that comes out every two weeks.
And if you don't want to do any of that, there is doing all the achievements, getting world completion, finishing Collections, or making an alt.
So in many ways, WoW and GW2 have the *exact same* endgame, just with slightly different focus: in WoW, new content required you to raise your Tier of gear to do the new content. In GW2, that vertical progression doesn't exist. Once you hit Exotic, you're done. From there, you're free to experiment, try new builds, or try different stat sets of gear.
One big different here being, that in GW2 due to level scaling, *all* the content remains valid, even when you're max level. That level 1-15 zone you've never seen: worth visiting even if you're level 80. In WoW, once you hit max level, going to lower-level zones didn't have any real purpose except if you were doing a completion thing, like world explorer, or grinding for rep.
So in a way, the "end game" in GW2 isn't that different from the genre standard, it just isn't quite packaged the same way, and there's more of it. You do the things you enjoy doing in the game: and if you're bored, you can stop playing and do something else, without worrying you'll be "left behind". It helps to not think about endgame when playing, and just think of "game". What do you want to see, what haven't you tried yet, etc. There are a thousand carrots you could chase in GW2, like making a Legendary, crafting a full Ascended set, or collecting all the minis. It just depends on what kind of carrots you like.