I think if you pick a concrete example of this phenomena (say, Java applets vs. WebAssembly) and you ask "so why didn't someone take Java Applets and update them, why do we need WebAssembly?", the answers to why this happens start to become more apparent. It's not so much that Java applets were good and then we decided they were unfashionable, as that Java applets were always kind of ugly and we eventually stopped tolerating them.
For examples from before say, 2000, say Turbo Pascal a lot of the answer is because the thing in question was a proprietary product so once the financially backed dev team stopped working on it users were forced to move on to something else. Other times it's because the thing was written for an 80's computer platform that no longer exists outside of emulation and retrocomputing collections. Sometimes it's that the graphical standards the original used were for hardware with very different capabilities and making the thing usefully work on a newer system would almost require a total rewrite anyway.
Even beyond all that, there's another problem: Software is fairly hard to do literature review for. If I want to know if a particular research idea has been done before, I can hop on Google Scholar and figure it out with a few hours of carefully constructed search queries. Doing the same thing for software is very difficult, especially because most products for the majority of the fields history were proprietary. As a consequence, we don't have our history available to analyze in any easily accessed form. The Internet Archive has been doing what they can to rectify this situation. (See: https://archive.org/details/BeyondCyberpunkMacintosh) Nonetheless, there are still serious problems in this area.
I'm a younger person (23) who shares your frustrations, but I don't think that you can really wag your finger at people when there are real barriers to what you're proposing.