Interesting point. I remember that the University of Denver ended up with the physical plant of Colorado Women's College, but to what extent it assimilated it otherwise--faculty, staff, students, programs--I don't think I ever heard. Apparently Yale once had the notion that absorbing Vassar would be a quick way to go coeducational. I can't offhand think of other consolidations or proposed consolidations of colleges, though.

Given how many corporations do dwindle and fail, it's hard for me to believe that the lifespan would be categorically different. Even if it were doubled because of mergers, that wouldn't change the logic.