I feel like the people who complain that there is no end game are the people that fly through the content too quickly. I know people who finished the ShB storyline in like 2-3 days, not doing any sidequests and farming dungeons for gear. While it took me a little over 2 weeks due to life stuff and just taking my time seeing the new locales, doing side quests, FATES, etc. My best friend, who I got into FFXIV when SB was released, literally started ARR, skipped every cutscene and caught up to me in SB in a few days. He even got to lv70 before I did then complained that there was nothing to do so he quit the game after about 1-2 weeks.
I have been playing for the last 3-4 years. I've complained about the lack of end-game but that's because I have done a large majoriy of content throughout the years with the exception of Savage/Ex raid (which I skip because I don't want to deal with the stress and it's just not fun for me personally) Crafting which I've dabbled in a bit but ultimately get bored of, some of the beast tribe quests, and a lot more that I never got around to do. But even still, there is a ton of things to do in this game. The issue is that a lot of this content is old and really irrelevant if you're max level and most of it involves farming which can get mind-numbingly boring.
Eureka/Diadem was a grind for gear that basically was useless due to Augmented Tome Gear just being better.
PotD/HoH is good for leveling but is also a grind for the weapons.
Crafting/gathering another grind but will help in the long run with gil and pentamelding or repairs.
Beast Tribes unlock exclusive items
The new FATEs provide bi-color gems that unlock more items the more FATEs you do
Dungeon farming for glam (which is the real endgame)
Savage/EX/Ultimate for all the hardcore guys
All the sidequests for the lore-lovers and world building
Squadrons unlock exclusive items
Delivery quests
PVP would be great if the queues didn't suck.
All the Gold Saucer Stuff (LoV, Chocobo Breeding/Racing, Triple Triad)
Collecting all of the Aether Currents
Finding, buying and decorating a house.
Treasure Maps and Dungeons
Level other jobs/classes
Relic/Anima Weapons
I'm sure there's more. But before anyone says that there isn't much to do engame, make sure you really ask yourself if you've really done EVERYTHING this game has to offer. Sure, there are things that I'm not interested in but that's not to say that it just isn't anything to do once I've reached maxed level.