I didn't look close enough to see if what they're patenting is something specifically unique to Unity3d's implementation. It would have to be?
From the abstract it sounds like the equivalent of trying to patent Observer/Observable.
Maybe there is a history of patenting software architecture that I'm not aware of, I'm not an expert in patenting in software development.
Patenting such technology runs counter to the reality that this track of game engine innovation in particular has been one particularly notable for the open sharing of techniques and technology, in the interest of everyone benefitting from a better approach in core architecture that improves performance and reduces incidental complexity. At some point, it became a cultural norm that people were not going to hold their cards close to their chest on this core part of the game loop. There are a lot of areas where I'd be inclined to accept the idea of IP protections for game engine companies on an ethical basis: this isn't one of them.