I believe that there is a pervasive attitude that the fighter should be (is?) "the easy intro class."
The attitude is a holdover from early editions where it was actually quite difficult to keep a wizard alive long enough that they could be useful, and fighters were actually more fun to play at those early levels.
But the only way players of Magic-Users felt they got "rewarded" for their patience was to get to a point where they get to dominate the game, so god forbid there are Fighter-types who can keep up.
However, the stereotypical "fragile, useless magic-user" stopped being true about 5th-level in 3e, which (thanks to the new xp system) you got to inside of a few months of play, and simply hasn't existed since. So there's no reason to keep fighters tied down at high levels to make up for Wizards "not having any fun" at low levels, because the latter situation simply no longer exists. Of course, even all the people who do want fighters to keep pace with wizards don't always agree about what needs to be done to make that happen.
My two cents.