[Jach]

You're right that total memory can be a tradeoff since any GC will necessarily have some space overhead, the question is how much, and whether you can accept some time tradeoff in exchange for less space. So again it all really depends on the GC implementation (or implementations, e.g. standard Java can swap implementations too). Remember that Java was originally designed to run on embedded systems, Lisp has been used on very tiny hardware, and GC theory has been developing from at least the 60s. Memory is plentiful compared to those days.

My go-to reference when getting into GCs is http://gchandbook.org/ and it covers all this in the beginning. One old study tried a particular GC algorithm with Java and some various program benchmarks and found to match perfect manual allocation time (which will be better than in practice) you'll need about 5x the minimum memory, 3x gives you 17% overhead. I think anywhere from 1.5x to 3x is normal in practice since it depends on the application itself. There are tradeoffs everywhere and it's great Rust offers another one.

I thought JVM startup time was a dead horse. :) Sure native beats it, so does Python, but not by much these days.