That's a bunch of baloney in any campaign other than a high magic campaign where the Fighter (and Barbarian and Rogue) don't have access to magic items because the DM is terrible. In any other campaign they are fine even if they aren't the best at specific things.
And that’s fundamentally what it comes down to: players having fun. If a player doesn’t mind taking a backseat, the Fighter isn’t a problem. For anyone else, they’re better off taking a different class.