The US Government made ASML dominant when it allowed it to acquire (US Company) Cymer, Inc.- the company that was best in the world at the time at EUV. Merging Cymer's EUV work with ASML's meticulous perfection and delivery of the entire rest of the system is what made them the only vendor that matters for semiconductor manufacturers.

This acquisition is also what gives the US Government the ability to veto customers of ASML even today- this is why Chinese semiconductor manufacturing is so far behind, because the USG controls who can access ASML's EUV work.