I think long term this isn't really a tradeoff. Starlink exists to fund SpaceX ventures designed to significantly drop the costs of lifting bulk mass to space. That translates to even cheaper missions, which means space-based astronomy can become affordable.

What is a loss of some percentage of astronomical observations today, if it means putting a telescope on the backside of the Moon in 20 years, or a ridiculously large "virtual telescope" via a satellite constellation doing interferometry?