So what if we use our experiences and in-depth knowledge of a past protocol, take into account the flaws, and build something better? You say "re-implemented TCP" as if it's the only possible way to build a reliable packet protocol, and that it has no flaws, and we can't make any improvements to it.
TCP isn't alien technology we don't understand. We do understand it, and its limits, and its constraints, and that means we can build a better one next time.
The problem with coming “to the realization that they have re-implemented TCP” is that it was ad-hoc. In this situation, the re-implementation was done by people very familiar with TCP, both its strengths, weaknesses, and assumptions, who very deliberately set out to “re-implement” TCP to work better with how are networks actually are configured.
