> I'd be willing to bet over 99.999% of all deployed production web applications serving requests today -- has a bottleneck at the database and the network that dwarfs any overhead from language performance
A language is not just about overhead, it's also about capability. For example, your database is slow, and your web page needs to render by executing 20 queries. Will your programming language allow you to parallelize those queries? While your database/network may have high latency, they can still have good throughput.
This particular example is very real, and is incidentally relevant to the original post, since Python and Go implementations have different capabilities.
A language is not just about overhead, it's also about capability. For example, your database is slow, and your web page needs to render by executing 20 queries. Will your programming language allow you to parallelize those queries? While your database/network may have high latency, they can still have good throughput.
This particular example is very real, and is incidentally relevant to the original post, since Python and Go implementations have different capabilities.