Re: You are an astronomer - others are not.
Well, you see, money is fungible: what is spent from tax revenue on one thing can not also be spent on another thing. 'Budgets' are a fiction. If HST had not been built there would have been money for robot telescope, or more robot telesopes.
However I was wrong about something important. I said elsewhere that JWST is not expensive because is same price as HST: that's wrong. HST cost was huge bloat because of Shuttle & servicing madness: JWST does not have that silliness but it still is $10 billion: is vastly, vastly more than it should be.
For cost of HST could have put *four* Perserverence rovers on Mars, or built *ten* VLTs: forty 8.2M mirrors usable as interferometers and perhaps even as one huge interferometer. Each servicing mission for HST would fund a VLT (pointed out by someone else here: I did not think of this). Perhaps there are astronomers who would rather have one HST instead of ten VLTs. But probably not many. Or could have several much cheaper robot space telescopes (as JWST should have been) with shorter lives and several more VLTs.
Ah, but you say, that's not the point: HST was never about astronomy it was about humans doing things in space. Well, if you want that, then do things in space that robots cannot do: build cheaper robot telescopes for the astronomers and spend money for humans in space doing experiments which it is hard for machines to do.
Even better, if what you really want is human spaceflight (which I want too): cancel shuttle in early 80s when it was clear it was an elephant but before it had started to kill people and before it had eaten most of its cost, and build manned space flight system which is not elephant. Humans would today be on the Moon and probably on Mars if it was not for the idiot shuttle. And there very definitely are things humans can do on the Moon and Mars which robots find very hard. And the systems you built to do that could easily lift a number of robot telescopes as well. Indeed they could probably put those telescopes in much better orbits than the shuttle could.
But that didn't happen because of pride and Concorde fallacy of course.
HST has done (and still does) good science, but at an enormous cost, and it is not justified by some argument that servicing it is a good thing: people can do far more interesting things in space than service telescopes.
Well, I also now have maths to do which is more interesting than arguing on the internet. I am sure you will downvote me.