The thing to appreciate is that in academic science, $12000 lens is inexpensive; the scale is different from consumer and prosumer pricing. A typical project like this would get at least a million dollaras in funding (see https://www.artsci.utoronto.ca/news/astronomer-roberto-abrah... which shows they got $2M to buy lenses; 120 lenses * 12K = $1.5M.
I work with microscopes that cost $1M and just sit in a lab. That's not atypical for an academic or industrial microscope.
One of the biggest issues in modern science is that to make many discoveries you need to pay very high prices to get the latest and greatest hardware. I've been exploring how to make lower cost telescopes and microscopes (and definitely love this project), that are "good enough" to open up new areas of research/discovery for people with budgets in the $1K-10K range. But it's hard! So far I have mostly been relearning what people already knew in the 1800s and early 1900s, that is easily obtained off-the-shelf tech today.
The point is it's not that inexpensive for the optics. I've worked in an interferometry lab where we used high-volume photographic lenses where we could, and yeah, they were probably an order of magnitude less expensive than something made for the purpose, and real exotic optics were more than two orders of magnitude more expensive.
But talking apples to apples, a $12000 professional camera lens is closer to something like a $12000 research microscope than you think in terms of the build-or-buy decision. There's also a whole industry of telescopes for amateurs that are made in low volumes to much higher optical standards than photographic lenses that are mostly not that expensive. A top tier 6" refractor might be $15K and blow the camera lens away as a general purpose astronomical instrument, but it would not be nearly as fast, which is important for this application, and if you placed an order for 120 of them, you might get them in five years. Maybe. I'd guess that made-for-the-purpose tubes would come in within a factor of two or three of the off-the-shelf lens if you could find a supplier. They might even be cheaper. The project risk would be larger, and that might be determining also.
I work with microscopes that cost $1M and just sit in a lab. That's not atypical for an academic or industrial microscope.
One of the biggest issues in modern science is that to make many discoveries you need to pay very high prices to get the latest and greatest hardware. I've been exploring how to make lower cost telescopes and microscopes (and definitely love this project), that are "good enough" to open up new areas of research/discovery for people with budgets in the $1K-10K range. But it's hard! So far I have mostly been relearning what people already knew in the 1800s and early 1900s, that is easily obtained off-the-shelf tech today.