There's not going to much meaningful pushback on this comment because any (ex-)ASML employee is going to be super hesitant to share anything. So feel free to think what you want.
ASML is impressive because they managed to ship despite the code having been a mess. It’s a mad accomplishment of both engineering and organization (they solve the messy code problem by simply employing 10x the programmers than they might need if the code was better, and somehow that actually works! That’s impressive organization, cause conventional wisdom eg Mythical Man Month suggests you can’t do that)
I think it’s more that not many ASML people are on HN.