Item levels.

[HakuroDK]

*snip*

As someone who has played in a few MMOs, I'm not quite sure that's accurate. Item Levels have become more and more commonplace as a means of stretching out the endgame and keeping people playing longer. Traditionally, someone starts out with what some folks like to call the "Level 50 Default Gear", which includes the full set of Artifact Armor that you get during your Job Quests. From there, superior gear becomes available that could not be equipped prior, thus adding a buffer between a rookie at the level cap and a veteran who has been sitting at the level cap for a while.
Once you hit Level 50, there's a plateau. On that plateau, is 50% of the game you couldn't access before. And a lot of that stuff is really hard. But the rewards are great. Fighting through lots of different dungeons, earning marks, getting new gear, maybe even picking up some rare pieces in those dungeons.

Now imagine if the plateau didn't exist as it did. Same amount of content, same bosses, same difficulty level. But instead of Item Levels, the Level Cap was 90. Now, anyone who's ever capped can probably remark on the sheer exhaustive nightmare it can be to close the gap between the levels of 30 and 50. Those with help find it to be very easy. Those without would call the experience harrowing. Now, if the level cap was 90 instead, and all of the current content was gradually stretched out, there's just not enough content there to make such a grind worthwhile! And even if you did make it to Level 90, what then? What would be the point in playing anymore?

The plateau provides a position of relaxation in players to where they don't have to work so hard because they've already reached the plateau, and therefore can go at their own pace. Some will continue going at a grueling pace, others will instead opt to take it easy and run the dailies for the tomes they need. But usually, after about a week or so at that plateau, much of the content becomes accessible.

I'm probably not making TOO much sense here as I'm on my 22nd hour awake, but I just hope you'll try to understand why there is an item level rather than complaining about the fact that it exists.

Though I should add, to your last line, that with an actual level, it'd be the same anti-intellectual behavior to check someone's level as it would be to check their item level. The only difference is that one affects character stats directly and the other affects equipped gear, which translates to how that affects character stats.

Besides, if they raised the level cap, they'd have to add more abilities and quests every time. I should remark on how Arcanist almost got pushed to 2.1 because it wasn't finished yet, if that's any indication on how much of a chore it can be to do anything more to classes than mere tweaking of code.