> only to have it completely obsoleted a few years later

Not really. There aren’t as many fundamentally new ideas in modern tech as it may seem.

Web servers have existed for more than 30 years and haven’t changed that much since then. Or e.g., React + Redux is pretty much the same thing as WinProc from WinAPI - invented some time in ~1990. Before Docker, there were Solaris Zones and FreeBSD jails. TCP/IP is 50 years old. And many, many other things we perceive as new.

Moreover, I think it’s worth looking back and learning some of the “old tech” for inspiration; there’s a wealth of deep and prescient ideas there. We still don’t have a full modern equivalent of Macromedia Flash, for example.