Is there anything meaningful/gratifying to do in this game that's not MSQ?

[Mwynn]

Gathering and crafting also requires me to finish MSQ before I can reach a point where I can make any real money or obtain useful material

There is low level Recipes that are hardly touched, same for Furniture, you can basically make Millions out of that if not even more so.

Being a Lv.70 Gatherer just brings you into Markets that are full of competition, if not you won't be able to keep even up.
That's more likely due of some People putting 99x Stacks on the Marketboard and they certainly will undercut you extremely.

Speaking about 2.1 --> 2.55 Story, yes... they're full of fillers.
I wouldn't say the same to Heavensward / Stormblood though, there are a few but SE has learned of their mistakes and tuned the amount of Quests down.

Shire Gear was iLv.260 if I recall that correctly, upgraded via Heavensward Raids you'll get those Pieces to iLv.270.

That is basically enough until you hit Level 62 (63 if you count a Optional Dungeon and it's iLv.270 Loot), so in short if you expect Upgrades under Level 64, it's not happening.