ASML depends on lenses from a relatively small company. That company does not have interest in ramping production any more than they already have. They don't care how much money they're offered.
Nobody else can get the job done. So, as they say, it is what it is.
15 years ago, when I was there, Zeiss SMT also did the light sources (discussed elsewhere in the thread), btw, not just supplying the lenses. Don't know if that's still the case. I don't know exactly what the lens/mirror systems for EUV look like, but the "old" 193nm ones were something to behold.
Zeiss has more than just SMT (the guys that build the EUV mirrors), they have consumer products, a medical technology arm and one that is working on optical quality assurance and research microscopy. Alltogether 40k employees and around 6 or 7 billion Euros of annual revenue. Small on a global scale, but not that small.
Great company for engineers, by the way.
Workforce or valuation? It's no secret that these tech companies are over-inflated, at least recently there seems to have been a correction. Companies like Zeiss are much more solid at least.
Nobody else can get the job done. So, as they say, it is what it is.