Looking at 2E first (since I'm more familiar with it than 1E), fighters get tons of followers. If he rolls well, he can get up to 151 followers, with one of them being 7th level, 30 of them being 1st level, and 120 being 0th level. At the worst, he gets a 5th level follower, and 70 other followers (10 being 1st level), all armed and ready to fight.
Compare that to other classes.
Fighters get up to 151 followers
Paladins get no followers - 0.
Rangers get 2d6 (7 on average), most of them animals.
Wizards get no followers - 0.
Clerics get 20 - 200 followers, for an average of 110 followers.
Druids get just 3, but only after hitting 12th level, not 9th.
Thieves get 4d6 followers for an average of 14 of them.
Bards get 10d6 or an average of 35.
So we have a situation where paladins and wizards get no followers, druids get just 3 (and even then only after attaining 3 levels higher than the level where everyone else gets them), rangers get on average 7 (and those are mostly animals), thieves are a little luckier...they get 14 on average, but clerics and fighters get into the hundreds! On average, fighters get 111, clerics 110. The next best is the bard with a third the number.
In 1E it's a bit different, but there barbarians can call hordes of up to 2,000 members (at 11th level)!



Even at 8th level he can call up to 1,000 barbarians.
Why would a super successful, highly charismatic paladin not attract followers? Or a powerful, famous wizard not attract apprentices? And now that I think about it, it makes more sense for druids to gain animals as followers than it does rangers.
Thinking about it once again, it seems a bit...off.
