I think in general, there are enough non-conference matchups in basketball to get a pretty good idea of how the conferences compare to each other. Football is so limited in that regard, with each P5 team probably averaging about 1 non-conference P5 opponent in the regular season.
For a look at the parity of college basketball right now, of the top 10 teams on Kenpom, the only ones to not have a loss outside of the Kenpom top 25 are Houston, North Carolina, and Illinois. Beyond that, 5 of the top 10 have a loss outside the Kenpom top 50. Except for the very best teams against the very worst, pretty much every game outcome at this point in the season is far from certain without it being a huge shock.