I decided to read the entire thread, and my final conclusion remains roughly the same. Although "not serious" is perhaps too harsh, the author does not provide the level of detail I'd expect of someone asking for 250 thousand dollars for their existing work (as well as 750k for future work).

The most information we got was "on a few simple benchmarks I'm seeing about a 70% speedup vs master for both default and LTO configures." However, this information is almost completely useless. What benchmarks? What architectures? What hardware?

It would take the author 5 minutes of their time to say "here's the benchmark code I ran, it executed in [time] on CPython master commit [hash], and [lower time] on my patch, running on a machine with [hardware]." To be completely honest, I fail to see why they are not providing this information that would make their proposal significantly stronger.