Or no Hobbits at all...

[William Cloud Hicklin]

Tolkien sold all his rights to LoTR/Hobbit, so why is the estate getting anything at all?

Well, yes, JRRT sold those rights; but the purchase price he got for them was some amount of cash up front *plus* a promised share of the income. Apparently New Line rather neglected that bit. Just like they did with Peter Jackson, and Saul Zaentz, and the actors, all of whom have had to sue New Line to get their share.