I mean, the first mod for Bethesda games tends to be murder children and nudity, so why don't we include that in the base game?
I'm being hyperbolic, but I don't consider this a good faith argument.
Yours?
It doesn't sound like one, admittedly.
EDIT- And I'm not sure what do you even mean with "sensible". No one was questioning if the game can or can't work with a party of 4, 3 or even 1.
The argument was (predominantly) that it would be better with a larger one, for one million reasons we already argued to death and back one million times:
- more chances to have companions interact with each other and with the player
- more access to their quests and story tidbits.
- more flexibility in party composition where even not optimal, prioritary or minimaxed characters would be welcomed. Or partially redundant ones.
- more chances to make more use of loot of different types in general.
- more tactical options and less reliance on RNG to pass successfully critical situations.
etc, etc, etc.