Re: Boosting
>The upgrades have replaced vast amounts of the telescope over the years, but I'm not sure you could reasonably have built several new versions and launched those for less than the maintenance costs.
Hubble cost many times more than it should because of the service missions - they made it a "manned mission" and imposed much more stringent requirements, and launching from the Shuttle into an orbit that allowed servicing also meant that its operation was severely compromised.
The storage cost for the years after the challenger disaster were estimated to be about what a comparable unmanned recon satellite costs.
Some of this was the politics/environment of the day (which ran on into JWST) - starting now you would probably build a family of identical spacecraft busses with upgraded instruments and launch the with the much cheaper commercial options