Rivalries, like everything, mean different things to different people. Michigan and OSU will both each consider the other their rival and I'm convinced nothing will change that during my lifetime. No matter how good MSU gets, and no matter how much MSU considers Michigan their #1 rival, Michigan will never be the same. Same goes for PSU with OSU.
Michigan / Minnesota play for the little brown jug and is considered a rivalry, but I don't think the players get charged-up for that game more than any other conference game. Same with the OSU / Illinois rivalry for the Illibuck.
PSU used to have yearly games with Pitt and WVU. They have played Pitt 96 times, and they have played WVU 59 time. Pitt is only 130 miles away, and WVU is only 180 miles away. Coming into the B1G and no longer playing Pitt and WVU, they lost those rivalries and never found a new one in the B1G b/c the good teams already had rivals that they had been playing for decades. You can't just manufacture a rivalry.
So PSU was stuck in no man's land where they don't play their traditional rivals and don't have a rival in their own conference after 20+ years in the B1G. The addition of Rutgers presents the perfect opportunity for this to develop. 1 - neither school currently has a rival that they play on a yearly basis. 2 - they are in close proximity, 230 miles. 3 - they go after many of the same recruits. 4 - there are many NJ residents who go to PSU for school and return to NY/NJ to work so there is a good chance that RU alumni are dealing with PSU alumni all the time. I mean the NJ MVC has its own license plate for PSU alums. All we need now is - 5 - some late-season games where the B1G East title is in play and we'll have a rivalry. Forget past history, when the games start being played at the end of the year (starting next year) if they are meaningful games then it will naturally become a rivalry.