At that you absolutely don't need a special expensive institution to teach you how to behave. A century ago it might have made sense - formal conduct was rigid

At that you absolutely don't need a special expensive institution to teach you how to behave. A century ago it might have made sense - formal conduct was rigid and failure to adhere could displace you out of aristocracy. You needed to know your proper dinner routines and manners perfectly. You needed to know the retinue of history and contemporary science topics popular in the era to not be left looking ignorant of a conversation. Of course that later circumstance was only applicable in an era when major scientific advancements were slow and costly to disseminate. Thats why it required the infrastructure of a university to supply it. I feel like that might not be quite as much of a barrier today, and nobody is expected to stay current on all news - there is simply too much, too fast, even of the purely scholarly variety. While I don't think your average 18 year old is of "mature" character or often fit to participate in normative adult culture it also isn't a danger to them to have to learn how in the moment. The worst that happens is they lose a job or two and rebound - it isn't a lifelong disgrace in an insular society anymore.