But why? Mostly ideological I would guess. The sorts of people the were/are running the FSF didn't want to involve themselves with the sort of 'dirty' compromi

But why? Mostly ideological I would guess. The sorts of people the were/are running the FSF didn't want to involve themselves with the sort of 'dirty' compromises needed to raise significant funds and end up beholden to large, almost certainly corporate, donors. This is one of the main reasons why Free Software lost the 'war' to Open Source back in the day.