There’s been a lot of unmanned exploration during the shuttle era. Given the fact that the shuttle was the cheap option, and actually had a lower budget than the original cheap option that was presented to Nixon, it accomplished a lot. It kept the Hubble going, helped build the space station, tons of science happened up there. Yes we could have advanced the ball further, but that option was removed when Nixon decided the space program was a Kennedy thing and pushed them to the cheapest way to continue. Trying to cast it as a complete failure and total waste of money is just plain silly.
Not saying it was a total waste of money or a complete failure...of course we learned from it, and gained technology wise in the process. The question is was the amount of gain worth the money spent? I personally don’t think so.
BTW, the whole concept of the shuttle’s value as a ‘reusable’ platform is very silly, given the cost to return it back to ‘flight ready’ status after a mission. That albatross had to be stripped down and almost completely rebuilt every time it flew. Not efficient at all.
The shuttle had its’ place, and did have some value. But it was obsolete very soon after it started flying. It should have been more transitional, and should not have lasted as long as it did.