Even if it's disabled, like do you really think they'd just install their own OS? Or find away around the part that's disabled? Like you can still jail break an iPhone
AFAIK the optics have to be regularly cleaned, calibrated and replaced. And by regularly, I mean daily/weekly for some of that.
The process is a carefully guarded trade secret and intentionally difficult. The companies that own the machines are not allowed to have employees who are trained in the process. When you buy those machines it comes with a service contract from the manufacturer. And the manufacturer is ASML - a Dutch company.
Again, if THATS the case, then you just find your own parameters and experiment with your pwn till its right. You don't give up on the last car on earth if you're a mechanic and they took the battery out. You find another that's compatible or research how you could make your own.
Saying that a "company" with "trade secrets" is just a dumb patent road block to scare off consumers
You underestimate how extremely complex semiconductor photolithography is. It is the most complex manufacturing process ever conceived by humans to produce the most complex systems ever built by humans.
China afaik is currently doing exactly that, as well as a few companies in the United States. Its not something just as easy as "experimenting yourself" (although, that is a very simplified way to look at it.) This is decades of research, with billions of dollars. Countries like China can socialize some of these aspects, and seems to be doing very well. It still takes time and money, and research. All the while, the current leading companies are still also furthering their own research.
The fact is these are high tech machines. To follow your example with the car, you don't need to replace the battery but an ECU, for which there are no available design and you have no idea how to build it.
Add to this that probably if you make a mistake in your try, you destroy the machine.
Basically what ASLM is saying is that they can brick the machine with a software update and even if not bricked the machine cannot run long without specialized maintenance and spare parts (that they obviously will not provide anymore). True, China can try to clone them, but even if/when understand how to make them, you then need to make them, a thing which seems out of question for now for China (else they already would have such machines).
i would assume it's intended to be irreversible, like contamination to the point of permanent dysfunction. Though im not sure how that would be possible, i assume it is.