Some ground-based observatories have been productively operated for nearly a _century_, with improvements in instrumentation providing leaps forward in sensitiv

Some ground-based observatories have been productively operated for nearly a _century_, with improvements in instrumentation providing leaps forward in sensitivity. That amortizes the cost of the observatory (mirror, site, etc.) across many years. Even with cheaper launches it's much harder to get that benefit in space--servicing missions are much more expensive than driving up a mountain...