ASML made a technological step after a decade-and-a-half of R&D. They invented and commercialized a new type of laser, which allows the EUV production process.

ASML is the reason the chips of the past two years have been making such performance gains, after multiple years of marginal improvements.

They are also the only thing giving the EUs bid for Semiconductor independence any credibility.

Apparently there's a use for tax havens in the EU after all.

Which is why it is so odd that the differences between them are as large as they are. If they all buy the same ingredients, why is TSMC's secret sauce so much better?

I hear ASML works like an extremely high-tech consultancy. The tech developed for contract a is not available for contract b, so you can't just call ASML and ask for the same machine they sold to TSMC. That's what I've heard, anyway.

Weird, one would think they'd try to productize and scale as much as possible, but if there are just single-digit amount of buyers, maybe not?

ASML only provides part of the chain to produce a chip, mostly focussed on the lithography step. There are a dozen steps in the production chain around it.