I love the space program. The argument that it provides good ROI in terms of incidental technology R&D is weak and even counterproductive.

There is some return on that investment but it's necessarily much lower than ROI for direct investment in the needed non-space technologies. I do think there's some argument that we wouldn't spend the R&D at all without the space program, but that's speculative and still doesn't make the ROI worthwhile IMHO.

What makes the R&D worthwhile is space exploration itself. That is of incredible value itself. If you start trying to justify the cost with incidental tech development, you implicitly agree with the framing that space exploration really isn't worthwhile and needs other benefits to justify it - you undermine what you believe in. It's like humanities professors who argue that a history degree has good value in the job market - it does somewhat, but they are accepting the framing that their field and college education has no other value but early career employment and income, instead of life-changing understanding and skills (really embarassing for humanities professors who should understand framing better than anyone!).