Again, litigation and patent trolls are nothing new to the community. Claiming China in this case sounds like a crutch to wash off their own image after doing fishy thing themselves.

Prusa's primary opponent in this space would be Bambu--who, to be clear, are rattling their saber about patents, and they suck for that. They also have a better, faster printer that has its full feature set available on release, and Prusa does not.

I am more annoyed that Prusa is doing a bad job of shepherding open source and shipping bad products than that Bambu has a closed-source better one.

This is very close to the academia/industry divide. Academia (the public) spends an enormous amount of money investing in research to discover something novel and effective, or makes a large efficiency gain. Industry reads that, and implements it, with some minor tweaks. This, products are made for fractions of the cost it would have otherwise cost to make, with large improvements over previous capabilities, due to the work done in the public sphere. Effectively very similar to open and closed source.

To be clear, I'm not sure your analogy makes sense for the bambu printers vs prusa situatuon. If anything, prusa did not spend enough money actually advancing their tech. They are still deeply attached to their good old bed slinger design in 2023, and they literally just implemented the same thing with minor tweaks for years until recently. They rested on their laurels which was fine when the 3d printing industry was stagnating, but not anymore.

Bambu lab on the other hand came up with something pretty good, very well integrated that has basically taken 0 from the prusa designs. So it's not really closed source profiting off of public or open source work. Maybe for the slicer, but that's it.

Just compare the abysmal performance and quality of prusa's MMU that still really sucks almost half a decade after they originally released the product. Even if they are super expensive too! While on the bambu printers... It just works.

Point of clarification: could they file suit or have they started doing that?

In other words, is this a fear of something that might happen or something that is currently ongoing?

Or, to put it another way, is the simply rationalization for decision to close source made for other reasons or an actual reason?