The Case for Smaller Telescopes

One genre of reasons is structural. Astronomy is funded in decade-long blocks where almost all the money goes to a mega project like the James Webb. That structure - big decadal chunk - might be partly to blame.

A related reason is historical. Summing images wasn’t possible before digital imaging, which is only about 20 or 25 years old in astronomy. Since funding is decadal, thats actually not many generations of funding, so there haven’t been many chances to focus the community to use the last 5-10 years of tech.

Also, I think - somewhat cynically - that the telescope builders are mostly not software people. To them, building a next-generation mirror or lightweight gimbal system is the interesting challenge worth funding, not software stacks for combining images.

Another possible reason is fixed costs: cooling, the enclosure, and site costs like power and road access would be paid redundantly.

But overall, I have not found much disagreement when discussing this with actual astronomers (mostly at the University of Washington and Princeton).