My napkin math:

According to my research, these machines can etch around 150 wafers per hour and each wafer can fit around 50 top-of-the-line GPUs. This means we can produce around 7500 AI chips per hour. Sell them for $1k a piece. That's $7.5 million per hour in revenue. Run the thing for 3 days and we recover costs.

I'm sure there's more involved but that sounds like a pretty good ROI to me.

A photolithography machine doesn't etch anything (well, some EUV machines do it as an unwanted side effect because of plasma generation), it just patterns some resist material. Etching is happening elsewhere. Also, keep in mind, you'll need to do multiple passes through a photolithography machine to pattern different steps of the process - it's not a single pass thing.

The catch is if you started today with plenty of money (billions of dollars!) and could hire the right experts as you need them (this is a big if!) there would still be a couple years between today and producing 150 wafers per house. So the question isn't what does the math look like today, it is what the math looks like in 2 years - if you could answer that why didn't you start two years ago so you could get the current prices?

What about the $10b to build the facility (including clean air/water/chemicals/etc)?

that's 100% yield which ain't happening