Whether one agrees or disagrees with the premise regarding martials and spellcasters, you cannot deny (at least on Enworld) that this "player/table problem" comes up often.
How often does it need to come up, in order for it to be a game problem?
So all these players/tables have limited imagination?
The game's combat speed, especially after level 4, comes up often too. The game's short rest/long rest comes up often too. The game's "adventuring day" and what should be in it comes up often too. The game's weapon list and its lack of influence on attacks comes up often too. The game's skill list, and how it is too detailed or too short, comes up often too. The game's species and their attributed feats comes up often too.
So since all those things come up just as often, do they also need to be fixed? Must we streamline combat so players can only do one thing per turn in order to make it move faster? Must we only use long rest so as to not allow certain classes to have an advantage when using the short rest system? Must we require DMs to have four encounters per day no matter what the storyline says? Must we make weapons more complex, allowing them to interact with different armor or do different damage? Must we expand the skill list to include four of each ability to make sure everything is "balanced?" Must we allow everyone to just choose from a giant list of species' feats?
All of the above have been mentioned many, many times. In fact, the one I left out, removing abilities like strength, dexterity, constitution, etc. has probably been mentioned more times than any of these subjects, including the "fix the fighter" threads. So, should we remove the abilities because a group doesn't like it?
The point is, the fighter
IS a problem - but only for some tables. And, from what I have read, these tables don't want to sacrifice anything, they only want to make the fighter stronger. It's guised as under more options. But, in the end, it always boils down to: "My character can't do that, and I want them to be able to do that, but also keep everything they already can do."
Place it under the comparison model: "Compared to the 20th level wizard, my fighter is terrible."
Place it under the microscopic model: "During a round of combat under these exact conditions, I only deal 22.4 points of damage."
Place it under a secondary/tertiary model: "The fighters at my table don't even attempt RP and skill checks because it requires magic."
Place it under any of those, but refuse to place it under the actual model for which it is intended: The player, playing at a table, with other players, under the conditions the DM (who has ultimate control over the environment and encounters) has set. That is what is happening, which is why you have a debate.