Not just it would be foolish for the capital already spent, but the James Webb Space Telescope recently launched 100% relies on Hubble for the immense majority of its operations, as James Webb can just take infrared and red images, whole Hubble handles all the color spectrum, so most astronomers requires images taken by both on the same areas for a proper context and understanding. James Webb+Hubble duo is producing massive amounts of advances in empirical science.
But, even more foolish is the situation with Chandra. Chandra is literally the only way we can see on X-Rays frequency on space, there is a whole subfield of physics and astronomy dedicated solely to X-Rays, and literally dozen of thousands of professionals relies their whole careers on Chandra keeping operating. If Chandra is canceled, then we will have a massive lose of human capital, and we will need to spend decades again to recover it, if there will ever the political will for that in the future.
And, even more absurd, the professionals, whose careers are fueled by Chandra, are also some of the most prolific and profiting professionals which have impacted positively medicine, computation and other technologies recently. Discarding Chandra is not just a loss of science and human capital, but a literal net negative of money as well, that is returned as increased economic activity through taxes.
Canceling Chandra without a replacement ready is the equivalent of shooting all humanity on the feet, without anybody winning, and everyone taking the shoot.