> you're only going to invent RSA or blind signatures or zero knowledge once.

Well, maybe. Sometimes things that are discovered are lost or go completely unnoticed, so progress is not always monotonic. For example, for a long time it was believed that John William Strutt first documented dynamic soaring [1] in birds in the 1800s, but just recently (2018) it was found that actually none other than Leonardo DaVinci documented the phenomena in his notebooks centuries before [2]. People just didn't notice or forgot, despite those documents being some of the most poured over in history.

[1] https://en.wikipedia.org/wiki/Dynamic_soaring

[2] https://royalsocietypublishing.org/doi/10.1098/rsnr.2018.002...