> 1GB is plenty for almost every case I've seen, 10-20x the need

Couldn't have seen many then! Maybe you should look elsewhere.

> Yes if you're running a repeated full OS underneath (hello VMs) then it'll waste more.

Docker is not VMs. Other people have stated this.

> I run (regular) .NET (8) in <50mb, Javascript in <50mb, PHP in <50mb. C, Perl, Go in <20mb.

Good for you. I run web services that are heavier. The container has nothing to do with it.