The PAC brings in more money, and about the same on a per-school basis. Adding Texas and Oklahoma (plus their upcoming new TV deal) would vault the PAC12 well ahead of the Big12 financially. The only issue is (as you pointed out), it doesn't matter if the PAC12 average is substantially higher than the Big 12 average, because in the PAC12 they'd get the equal-revenue split, whereas in the Big12 they get favored status and an unequal share.