I suspect eventually there will be a big lawsuit where the blame can be laid on negligence in the software development and the incentives might change somewhat.
"Perceived"?
It's very rare that shipping later because of $quality-concerns is profitable. In most cases, that "later" never arrives anyway.
You might be inclined to suggest that that could have been prevented if only they'd used formal methods. Perhaps that's true. It's something that could have been prevented in many different ways, though. Yet it still happened.
And yet, there almost certainly were lawsuits. So maybe you found evidence that perfectly counters my theory. It changed software, but only a little bit. Very little, given the magnitude of what happened.
There seems to have been something akin to an "accident chain", where a large number of things went wrong. Had any one of these things not happened, there might have been much less harm caused, or even no harm at all.
I will admit to being peevish about stuff like this. Some of the failures with Therac-25 were systems failures that had nothing to do with software per se (I'm not counting "software hubris" as a software problem). They were failures of process, problems with hardware interlocks, and even UI bugs that made the software confusing to operators.
I have nothing against formal methods, but they're no substitute for a deep and abiding paranoia.
I'd argue that, if there was going to be a needle-mover lawsuit, it would have happened by now. Until there is evidence that it will happen, we can continue assuming that it won't.