The license contract is only partially relevant in this case. It will no doubt, as LoDebar stated, contain many clauses for either side to terminate (or prolong). For companies such as AGE and Nexon, nearly all choices will be based on profitability of the product.
From what we as players can see is that content (ep6) has been rushed in, and the frequency of gear-set releases increased as well. From a logical point of view AGE is running out of "tier teasers" in their available selling content. They kept back some of the EP6 content in-game, but last months has mostly been the same already for tiers. Players who have their gear linked, max OJed (and double OJed) and enchanted to 20 are all top spenders who are losing incentive to spend. So purely from a gamers point of view we can predict a drop in sales due to the business strategy AGE has portrayed.
Somehow Nexon had a pretty strict deadline for EP6, otherwise they would not have released it as buggy as they did.
Of course we cannot tell what choices will be made, but it's a given fact that staff hours from AGE for Shaiya have been reduced. We cannot see the exact details for sales, but I expect that the reduction of staff indicates lower sales. I do not know if Nexon receives a percentage or a fixed amount each month, but if sales are dropping there will be a point where running Shaiya is no longer profitable for 2 companies in a producer/publisher construction. When they reach this point, it mostly depends on Nexon what happens, AGE cannot really cut on hosting cost a lot (they already merged servers) and already stripped their staff down to nearly a skeleton crew.
I bet many bug fixes & patches (such as loss of Goddess zone, class balancing, map glitches, ep6 bugs) are not coming due to arguments on who has to pay for them.
PS. From what I can see the server machines are owned by AGE, not by Nexon