That, IMHO, is more of a legacy result of the original premise of the game, that each PC is basically a self-interested loner with no significant backstory. Not that you can't construct such a story a story, but the game is antithetical to it, as designed. Something like Beyond the Wall illustrates this perfectly, a game where you do start with a specific setup, and it is an OSR type of game too.
Modern D&D doesn't need to have this issue, the players can simply design a team, from day one. This was really the mode in which 4e works best, though 5e is good for that too. Instead of 'random collection of strangers' you can be "The town misfits. Drafted into the town guard, the Mayor sends you out to solve the mystery of the disappearing farmers." Of course he half hopes you all won't come back, but...