Tentative theory on why a team like UVA was the first to lose to a 16 seed.
I would have expected the first loss to come from a team built on lottery talent like the Fab Five or Tark era UNLV or DC era Syracuse or a Coach Cal team looking past their first round opponent. (the Mourning-Mutombo Georgetown team that almost lost to Princeton as a template).
But it was a disciplined defensive "system" team that dominated the toughest conference in the country. It may be that UVA was built to neutralize talent disadvantages against the likes of Duke, North Carolina, etc. Which is successful, but negates their advantage when they play a team like UMBC. The playing field is leveled. So teams like Duke and Villanova roll over their early round opponents on the strength of their talent, but UVA has to grind it out. And if a team like UMBC hits their shots, an upset is in play, whereas lottery pick teams can just run over them. I don't really like this, but I think it makes sense.