There's no downside to ordering a machine in 2030 an cancelling it later if it turns out you don't want it.

The further out an order backlog is, the more orders get put in to hold a spot in line.

There's a cost to breaking contracts like these. You can't change your mind two years down the line without paying a fine. ASML isn't stupid.

That said, computers are here to stay. Even if FABs can't sell chips at ridiculous prices, there will be a return on investment on these machines, even if it's not as high as originally hoped.