Ah. You refer to the "write once, run anywhere" marketing slogan at a time when there was a lot of JVM-to-JVM variability and JVM JITs were not very advanced. I didn't buy that slogan at the time (look at aaaaall that open source code running all over with ./configure) and always hated Java's crazy boilerplate verbosity combined with a culture to defend it as somehow "better".

I mean, it's not like people ran Internet servers on such vastly different CPUs/OSes or that diversity was such a disadvantage. DEC Alpha was probably the most different for its 64-bitness, but I ran all those open source Linux/C things on that by 1996..97. But we may just have to agree to disagree that it made a lot of sense for that reason. I have disagreements with several high profile SiValley "choices" and I know I'm a little weird.

Anyway, I don't mean to be arbitrarily disputatious. Focusing on what we do agree on, I agree 100% early Java stdlib's being bigger than C/C++ & early STL/template awfulness was a huge effect. :-) C++ like keywords and lexical sensibilities mattered, too. PLang researchers joked upon Java's success that C's replacement sure had to "look like C". But I think programmers having all their lib needs met with very little work matters even more and network-first package managers were just getting going. A perceived-as-good stdlib absolutely helps Go even today. Human network effects are a very real driver even among very talented engineers.

Maybe since CTAN/CPAN?, that often comes more from popularity and the ecosystem than "what's in the stdlib". Even before then there was netlib/fortran algorithm distribution, though. Node/Rust/Python worlds today show this.

How to drive popularity in a market of ideas competing for it is hard/finicky or the biggest marketing budget would always win and people could also always just "buy reputation" which empirically does not happen (though it sure happens sometimes which I guess shows ad spend is not wasted). Even so, "free advertising", "ecosystem builds going exponential", etc. - these are just tricky to induce.

The indisputable elephant in the room is path dependence. Fortran, still somewhat reflective of people "stacking punch card decks" to "link" programs in the 1950s, is still used by much modern scientific research either directly or indirectly. Folks were literally just figuring out what a PLang should be and how interacting with these new things called "computers" might work.

But path dependence is everywhere all around us.. in institutions, traditions, and technology. It's all really a big Humanity Complete discussion that spirals into a cluster of Wicked Problems. Happens so fast on so many topics. :-) If you happen to make something that catches on, let us hope you didn't make too many mistakes that get frozen in! Cheers!