I think it comes down to US and UK in terms of general science research. I would include Japan but language is an issue (for many). Despite what the average math and science metrics in the US imply, I actually think it’s a direct result of more practical approach to education in the US. There are unbelievable opportunities for young students who want to excel in sciences. I was around graduate level research environment since the 8th grade. And I would say it wasn’t all that unusual as long as you knew where to look. Access to science research is unparalleled in the US.