Mhmmm. Yeah I wish the default were to not use a proxy. Though to be fair I'm not sure exactly what the performance implications would be.
From what I understand, the proxy also helps people make sure that an upstream deleting their GitHub repos doesn't result in builds breaking on new machines that don't have it cached locally. Imagine the problems that could happen if someone new joins your team, runs `go build` and then one of the vital dependencies 404s. The other problem is that it's Google so their perception of "not much traffic" is "biblical flo…
This is a consequence of what IMO is another bad decision by the Go team: having packages be obtained from (and identified by) random github repos, instead of one or more central repositories like Maven Central for Java or crates.io for Rust. The proxy ends up being nothing more than an ad-hoc, informally-specified, bug-ridden re-implementation of half of a central repository, to paraphrase Greenspun's tenth rule.