What will that change?
Ubisoft invested their money in the game, and judging by all accounts, the game didn't pay off. Why would they continue to waste their money on a losing game, providing support, refunding money, and especially giving away the rights/source code for free? It's not in their interest, and they would never do that.

Imagine you sold a used car, and some time later, the buyer comes to you, complaining that the car broke down, demanding that you fix it at your expense, or refund the purchase price (which you no longer have), or give him your personal garage with all the tools so that the buyer can fix the car himself. And it's not like you're in a great financial position to begin with – let's say you're already in debt and paying a mortgage. And it's not about who's right, but about the fact that you simply can't afford it – for you, money is a matter of survival.

Selling the series to another company is a more realistic option.