If you're into go, it's not too hard to get very small (<5mb) shippables by statically compiling against musl and using upx. Here's a somewhat scrubbed Dockerfile for a gRPC/rest service I use at work: https://gist.github.com/jbergstroem/680cb7db6f90319dcd7666f3...
5mb still sounds like a lot, considering you could squeeze Linux 1.3 on a 1.44 mb floppy with a (compressed) rootfs... I mean does the runtime really do that much more than a full (although old) os kernel and a C library/runtime and apps?