Personally, I do think the satellites are going to harm ground-based astronomy, significantly.
But my (non-professional) view is that in the long term, these activities are going to bring down the cost of access to space, massively. It already has so far, with getting payloads to space having dropped to half of what they were even five years ago. And they are still coming down - well, unless you use a Senate Largesse Scheme launch vehicle that is, in which case the cost direction is up ...
My hope is that this continued drop in cost to access space would lead to, within 50 years, permanent manned research bases (like in Antarctica, not talking 'colonies') on the moon. This could lead to moon-based manned (for maintenance and upgrades) observatories, larger and more capable satellites in the various Earth Lagrangian points, even further afield, a higher cadence of satellite-based instruments that can be replaced (or augmented) every 3-5 years with more capable ones rather than the current ~20-year cycle, and so on.
So yes, over the next 5-30 years, ground-based observatories will be severely degraded if not entirely fucked. But I think the longer-term possibilities are worth this price.
Of course, others opinions may vary, especially those with vested interests in current and near-future (e.g. 30m-class observatories currently under construction) ground-based instrumentation, such as the current and up-coming generation of astronomical and cosmological researchers who depend on Earth-based observatories.