Fountain pens are a newfangled invention. Tnere’s no need for an ink bottle on every desk with fountain pens. Unless you’re writing a novel, you can fill them a couple of times a week. I used fountain pens probably from high school into my 30’s. I don’t like the force required for ball point pens. Today I use gel pens.
Ink bottles on students’ desks date back to the era of dip pens (aka nib pens), which held only the amount of ink that the narrow slit in the nib could hold.
I believe the reason ball point pens used to be so expensive is that the ball has to be precision engineered. Apparently until very recently, the Chinese did not have the capability to manufacture the balls, so they had to import them to make ball point pens. The story of their “breakthough” was all over the news earlier this year.