> At the end, the workplace is still arguably a far bigger deciding factor in the outcome than who you hire.

I really don’t think this is true. Are there any successful programming companies who just hire whoever for development work? All the top-tier ones have settled on being extremely selective. Of course, that could be coincidence or bias… but this practice is fairly expensive, so there would be nontrivial pressure against it. Furthermore, I think a lot of people can attest to working with both very good and bad developers on the same team - so even inside a workplace you see a range of individual productivity.