The article makes it pretty clear that Washer was not incompetent at her job, and that the role of the PATCO aftermath hiring spree was not to allow her to get hired when she otherwise couldn't, but to push her to apply when she otherwise might not have for specific personal reasons.
A different, and likely more productive, way of looking at a possible connection between PATCO firings and USAir 1493 is in the form of institutional knowledge lost.
I think a decent argument here is that the mass firing of a large portion of existing ATC personnel damaged the institutional knowledge and rigor of the ATC profession as a whole. What highly technical profession wouldn't be damaged by that? And this damage just increased the risk of serious mishap across the board; it suddenly became much more likely an ATC would make a mistake, and this one is one of those mistakes
