$4 million is pocket change for Valve, a company worth billions. And if you consider that they apparently sold around 1.6 million Steam controllers, that only amounts to about $2.50 per controller, probably not too much more than they might have paid for licensing to begin with.
I don't remember a controller from Corsair or this Ironburg company, are they resorting to patent trolling? Nobody can put buttons on the back? That explains why rear buttons are so rare and expensive, I wish every controller had them.
SCUF has been around for a while, and makes expensive customized console controllers with paddles on the back that duplicate functionality of certain front-facing buttons to make them easier to reach for competitive console gaming. Apparently corsair bought the company a little over a year ago, likely for the sole purpose of cashing in on their patents.
I would absolutely consider it patent trolling, seeing as this court case didn't happen until after Corsair bought the company, and after the controller had been discontinued. Actually, corsair's acquisition of SCUF happened within weeks of the Steam controller being discontinued, so it wouldn't surprise me if the pending lawsuit was a primary contributing factor to Valve killing off the Steam controller and clearing out the remaining inventory for next to nothing.
The buttons built into the grips of the Steam controller don't really bear that much resemblance to the paddles on a scuff controller either. It seems rather shifty patenting the existence of any buttons on the reverse side of a controller, especially seeing as the N64 controller had a button on its underside well before SCUF existed.