Indeed, 300:1 is pretty common in large lecture courses, even ones at relatively high ranked schools in fairly important topics (algorithms, for instance). And that's with the teacher having to give a different lecture to every single section every year, instead of just recording one lecture for everyone for the next several years.

Even more time is saved if we unbundled university education in general, so that the various paths and credentials are their own thing. IE, Intro to Poetry 101 isn't necessary for someone who's pursuing finance credentials.