I'm a mid-core player. I choose to not play end game. (What's the incentive?)

[Stormbad]

I consider myself a casual player (not even midcore) but I have
Beaten T1-13 when relevant.
Beaten A1s and A2s when relevant.
Killed every primal ex when relevant (including Sophia ex)
Every battle job to 50, with 4 capped at 60.
Every crafter to 60 with max stats for the new 4 stars
Every gatherer to 60 with max stats for the new 3 stars
Check out my lodestone for all my minions and mounts (including fenrir)

I hate grinding and I feel like I'm the slow one leveling up or doing special events, for example, I just got the yokai minion mounts and didn't even bother with the weapons.
I still have not got my POTD +30/+30 once yet, with only 3 potsherds.
I just finished my 240 relic only a month ago.
All I have achieved is from simply going at a slow, non-grindy, pace and I usually put in about 4-12 hours of playtime per week.
I choose to to end game because it is fun. Challenging content is fun. Coordinating with other people for a common goal is fun. And I hate grinding.
I think the game is literally designed around a player just like me.

So, not sure about your definition of midcore, or my definition of casual.

I'm not sure what the appeal of grinding a ton to make certain fight easier. And you bring up eve as a challenging grind, I guess paying for a sub over a time period is fun for grinders? For me, nope.

I have known RL people just like the OP, but they don't ever play these types of MMOs. They usually stick to lineage or eve.