The reason we're interested in Hawking has nothing to do with aesthetics, it has to do with science. The original works of a scientist may be of historical interest, but they are of no scientific interest. The reason we're interested in Hawking in the first place has nothing to do with the details of his original works, whereas the reason we're interested in Giambologna has everything to do with it.
For the original art, the main drive is its monetary value. Many piece of arts by famous artists are locked up in vaults. Not even locked up in expensive houses of the ultra rich for them to admire. In locked obscure vaults, gaining value until resold.
No, that's not true. The value of scientific knowledge, for example, is in its power to allow us to make reliable predictions about our environment and the consequences of our actions. That's not subjective.
> The historical context is definitely part of what makes art interesting.
Sure, but the historical interest in a work of art should follow as a consequence of the (subjective) quality of the art, not the other way around. If I were to make a painting, no one would (or should) care, but not because my painting would not have an interesting historical context. It's because I have no artistic talent and any painting I would make would be a bad painting. And 500 years from now it would still be a bad painting.
To use a more realistic example: Adolf Hitler and Winston Churchill were both painters, but no one remembers them for their art because it wasn't very good despite having an interesting historical context. Quality art creates an interesting historical context, no the other way around. Or at least that's how it ought to work IMHO.
Churchill’s also sell for quite a bit.