Please, please, please do STOP saying how the Space Shuttle (now retired) could be sent up to fix the Hubble. Yes if COULD. But the Shuttle system had major flaws:
1. Dangerous: the big wings, designed for dropping nukes on Russia over the poles, were useless in actual use and a source of deaths. (The tile hit the *WING* leading edge.)
2. Horrendously expensive: at ~$1.3bln PER LAUNCH it makes the ~$70 million for a much more reliable (at the time) launch on a Proton look totally, utterly, cheap. So expensive was the Space Shuttle that the "bottomless pockets" of the US Airforce ran away from it. It was basically only reserved for human-launch and cargo with them. At a massive cost.
3. Ridiculously risky: by today's standard the Hubble servicing flight is impossible. The radiation dose at ~600m vs 200-odd for LEO. The fact that the Shuttle did not have enough reserve fuel in that flight o make a second attempt at re-entry. The fact there was absolutely NO backup plan: they were simply too high, no other Shuttle could get that high, not other ship. If anything went wrong, they were dead.
4. The Hubble is ancient. At a cost of ~$1.3bln per launch at one a year, say, means that to keep the Shuttle flying just because one might need it ~15 years in the future means one has to pay, let's call it $25bln. Now even the James Webb, hugely over-budget as it is is about half that price. The Hubble is simply not worth saving via a manned launch and never would be.
In summary the Shuttle was a huge white-elephant that was so costly only NASA could afford to use it. The costs involved sapped so much of NASA's budget that other programmes were simply not done let alone shut down. It was a murderous mill-stone as people actually died due to such serious design flaws in the vehicle that those flaws could never be rectified (the huge wings). A technological dead end. As dead-end as having people in space-stations to photograph the Earth to spy on others, which was replaced by spy-satellites - cheaper, safer and better.