Conference-specific TV networks have become an enormous source of income, so conferences are incentivized to expand distribution of their regional TV networks by moving into new geographic markets. Schools, looking out for themselves, are trying to join the most successful conference possible, to get a cut of the mega-conference TV cash. We now have the so-called Atlantic Coast Conference with members schools in Texas and California. The Big 10 Conference, previously made up of 10 midwestern schools, is now up to 18 schools, spanning from coast to coast.
Athletes in non-revenue sports are taking long plane rides so they can go run on a track or swim in a pool thousands of miles from home, rather than at a nearby, longstanding rival's facility.
The revenue sports are generally happier, although you do get oddities there too. In football, teams generally only play 8 conference teams, so determining the best team in an 18-team conference where each team hasn't even played half of the league isn't terribly fair.
Any why are universities abandoning historic rivalries and doing so much wasteful travel? All for that almighty dollar.