I agree the rivalry would benefit from playing twice every year and have argued that in previous threads. However, at least 2 other major factors are at play here:
(1) With the proliferation of cable and geographical mobility, fan bases are less regional than they used to be. When I grew up up in NW Indiana, you rooted for either IU or Purdue basketball, or you simply didn't follow college hoops . Now you've a lot more people in the state following more of the 'national' teams like Duke, UK, or whoever the flavor of the year is.
(2) Nearly 50% of the students at both IU and Purdue come from out of state and hear absolutely nothing of the rivalry until they step foot on campus. And even then, the in state kids are not exactly rabid about indoctrinating them (see point #1).
(1) With the proliferation of cable and geographical mobility, fan bases are less regional than they used to be. When I grew up up in NW Indiana, you rooted for either IU or Purdue basketball, or you simply didn't follow college hoops . Now you've a lot more people in the state following more of the 'national' teams like Duke, UK, or whoever the flavor of the year is.
(2) Nearly 50% of the students at both IU and Purdue come from out of state and hear absolutely nothing of the rivalry until they step foot on campus. And even then, the in state kids are not exactly rabid about indoctrinating them (see point #1).