They've already extended the show once. Roundabout is not the type of theatre that wants to milk a show for years, from what I've seen. They're not-for-profit and interested in doing things for artistic motives. Sure, they make some good money along the way, but running the same show for years seriously hampers their ability to meet the artistic goals of the organization.
Production rights being pulled is nonsense; why would the company that holds the rights pull them when they're making solid money? It's literally a choice of getting money vs. not getting money for whatever company holds the rights - why would a profit-maximizing company choose the not getting money route?
BROADWAY: The Cripple of Inishmaan, This is Our Youth, If/Then, Hedwig and the Angry Inch (x3), Cabaret (x2), The Real Thing, A Gentleman's Guide to Love and Murder, Chicago, Les Miserables (x2) Disgraced, Finding Neverland, On the Twentieth Century, Wolf Hall Part I, On the Town, Fun Home; TOURING: Jekyll and Hyde, The Book of Mormon; LOCAL: The Twilight Zone, Anne Boleyn, Death and the Maiden, The Lying Kind, Chorus Line, Stupid F**king Bird