Yeah I think it is for 30 years but that affiliation Methodist signed is not exclusive, meaning that Methodist is free to obtain other affiliations if it wants to. I think Methodist can also buy out of that contract at any time.
That Chronicle article shows that at least the Methodist doctors are questioning the affiliation with Cornell, which (to be honest) is just silly. Have you guys ever heard of an affiliation of a hospital with a medical school so far away and that does not supply any physicians or residents? It kind of reminds me of a situation in which you are living in Houston and your new wife (who has already been married for a long long time to another man and sees him everyday) lives in New York. You pay that new wife millions of dollars a year (even though you never see her) just to say "yeah I am married to her."
I actually am an alum from Cornell's undergrad, and from what I know from the Cornell perspective is that Cornell only did this so they could suck big cash from Methodist and Methodist only did this out of desperation because they needed to be affiliated with a medical school for the US News Ranking of Best Hospitals. Cornell already has a big-time affiliation with NY Presbyterian, and I can guarantee you that no Cornell resident or physician is going to leave NY Presbyterian and go all the way to Methodist for any rounds or rotations.