Network Administrators: What are your thoughts on server side ad blockers like PiHole?

I attend a small college in New England, USA and have noticed that all of the computers across campus have ads on them. I understand that installing an ad blocker on each individual client could be a nightmare, but why are there no network or server side ad blockers in place? Is this just something my school choses not to do? Are there any companies/schools that have server side ad blocking? Thanks!