Yes, I am aware of Superior Technique and the Martial Adept feat. The fighter gets one paltry use between rests with the former, and have to choose between it and a Fighting Style. After that, they're still restricted to deciding on one single maneuver they can access. Why does the fighter have to fight tooth and nail for every little thing?
Yes the fighter gets a use between short rests. So you pretended this was specific to a subclass when it isn't.
artial Adept similarly competes between +2 to STR/DEX and far more effective feats like Polearm Master or Crossbow Expert. Contrary to what some people think, the 5e fighter isn't the same feat-loaded monster found in 3e and 3.5e!
There is no competition at all. If what you want is a PC that can do battlemaster maneuvers, then get battlemaster maneuvers. I take superior technique a lot, more than any other fighter fighting style. I don't take martial adept a lot, but I do take it occasionally on a Rogue or Eldritch Knight and in any case I take it more often than PAM or GWM or XBE (I take it less than sharpshooter though).
Get the manauver if that is what you want. I would say, get the maneuvers if you want to have fun in play and aren't sure what to get. If you want people to be impressed with your white room damage numbers, then take PAM as your feat.
You know the only people I have seen at the table disatisfied with the fighter they were playing are actually people who took the Pole Arm Master feat. I've seen this more than once. In one example he could not do squat for damage with his non-magic pole arm (and GWM) at 10th level. Most combats for the 2nd half of the campaign he was fighting with a magic mace and doing pretty good damage, but the polearm master feat was pretty much useless for the 2nd half of the game. I am sure they thought like you did when they took it and thought it would be a cool feat to have.
That character would have been better with any other feats instead of GWM and PAM! The problem with fighters is not the people who take Martial Adept, it is the people who take PAM and to a degree those that pretend it is a good thing to do or is effective. I have seen a bunch of GWM and GWM/PAM builds and although most of the PCs seemed to have fun only ONE seemed like a standout awesome fun character in play. That was in the Tyranny of Dragons campaign where we got a legendary Greatsword (PAM was still not relevant).
On the other hand I have thoroughly enjoyed every single fighter I have played doing what you are saying is a less effective build. I see the same from other PCs at the table. If I am having fun with my build, I don't think it can be called less effective if it is more fun.
The problem is not the fighter class. The problem is the build choices.
From levels 1-10, they have one more feat compared to other classes. Having to invest that feat in Martial Technique means you fall even further behind the caster classes compared to a fighter that goes all in on single target damage, the one thing they're good at.
They don't have to, but if they are not a battlemaster and they want to have battlemaster maneuvers then they should.
The fact is the story elements are all there for what you claim you want.
Have you considered that the reason many people are disinterested in low-magic 5e games is precisely because 5e doesn't offer compelling gameplay for low-magic characters?
No because full casters are disinterested in those games as well.
I play Rogues all the time. I play fighters a lot. Those classes RAW are VERY compelling for me and for literally almost everyone I have seen play them at tables I have played on (the PAM fighter mentioned earlier being the exception). You know what is not compelling for me? A Druid or a Barbarian and as such I have never played one of those classes. I purposely choose not to play classes that I do not find compelling and that works very well for me.
People today mostly don't want to play low magic characters. Even if they play a completely non-magic subclass like Battlemaster or Swashbuckler, they usually have some magic as part of their character through something else and they want magic items on top of that.
If people want to perform exciting deeds with their fighters, and the only way they are allowed to do that is pigeonholed into being magical or having access to magic items, of course they'll prefer high-magic games.
That is not why they want magic items in my opinion or experience and it is not unique to the fighter class.
This is hard to believe. You're saying people are not drawn to the class fantasy of being a knight or duelist, but to the mechanical simplicity offered by the 5e fighter chassis.
In the modern game no. Even if they are playing something a class like this they are ususally putting it on a Shaddar Kai or Drow or something else with magic or magic like abilities or taking a magic feat or multiclass. I see almost no one that wants to play a vanilla knight in shining armor that runs around the battlefield with weapons all the time.
I also never said a fighter was a simple class and as a matter of fact on this very thread I stated my opinion that at low level it is a difficult class for new players due to the resource management aspects that come on very early and the complicated subclasses which are closer to what most fighter players want than the simple sword-swinger.
I encouraging new players to play fighters is a huge mistake. If you are starting at 1st level I think many casters are actually better. It is a different story if you are starting at 5th level
Do you think a pared-down "blaster" class that also does nothing beyond spamming a single ray, without the additional customization and complexity afforded by Eldritch Invocations or Patrons, be one of the most popular classes too if it was included in the system?
Isn't that pretty much what an Arcane Archer is? I have had a lot of fun with them. It is probably my favorite fighter subclass (not the most powerful, my favorite).