I can kind of get it since we're talking about DnD specifically here. DnD's balance has always been horrible, specifically between casters and fighters. Casters have been better at the fighters both in and out of combat for several of the most popular editions. Casters could use a spell to do more damage than non-caster DPS, summon creatures that could tank better than the tank, mind control or buff to be a better face than the face, and do things that are outright impossible for non-casters like bring back the dead, fly, teleport, or practical things like communicate across the continent. And one character could do all that in a day. If one character is better than the rest of the party at their niche it is totally the game's fault.