I can't speak to there,experiences but there are two angles to take here.
1) Fighters lost quite a few things in defensive abilities over the years, and if we go far enough back, the inclusion of the rogue carved out a lot of the skill-based things the fighter used to do.
2) It is also important to recognize what other classes gained. The ability to leap 8 ft in the air, or 20 ft across a gap isn't as useful when every caster has a remote flying drone that they can send anywhere, to interact with anything, and without major penalties. And, every class is good in a fight. Fighters might, mathematically, barely, with feats and magic items, eek out ahead as the best at fighting, but if you play RAW with no feats and no magic items... they aren't even the best at fighting anymore.
Even if fighters lost nothing (and they did lose somethings) everyone else has GAINED a lot, which still creates a problem. After all, you don't play an AD&D fighter in a 5e game.