licenses usually stipulate that they're supposed to make X many figures a year, or rather, pay out a certain amount of royalties every year/month/quarter/etc. This is broken down by the toy types (including scales). No toy company can just stop producing toys all of a sudden, because they would pay a penalty fee AND still pay the promised royalties until the license expires. Which means, even if they were losing money, it's stilll in the toy company's best interest to continue producing the figures.
So Jazwares, making a mass market childrens toyline, would be producing far more figures than McFarlane to meet those goals. McFarlane has the collectors market license and we've seen how some companies just do ONE AND DONE stuff all the time. So that one figure that they're releasing likely meets the licensing requirements.
Whereas Jazwares needs to reach higher quotas and undoubtedly either not hitting them or under performing to Jazware's own bottom line. Since licenses are written to favor the current licensees, it's obvous that Jazwares is dropping the license themselves. Plus, with McFarlane also seemingly dropping support shows that consumer support wasn't all that great in general for Fortnite.
If you haven't noticed, there's no reports about Jazware's stock (Alleghany Capital Corporation) going down in price over losing that Fortnite license, because traders are able to track sales and noticed shit wasn't selling all that well to actually raise stock prices. As opposed to Mattel losing the DC license doing a number on Mattel's stock, because it actually made Mattel a lot of money. OF course, WB wasn't happy with sales and/or got a bad rep from Mattel's products, hence choosing not to reup with Mattel and splitting the license up to make it more affordable for other toy companies to make their bids (Spinmasters for ~1:18 scale, McFarlane getting larger scale figures, and Mattel continuing to make toddlershit).