[lawpoop]

That's sort of my point, if I understand you correctly.

There are two responses to "Hey, the site is slow!" One is "Well, that's because PHP/Python/Java is slow, we should start coding in C/etc". Another is "The codebase or architecture is probably unoptimized and/or poorly structured in some areas; let's identify, prioritize and start fixing those areas."

The slow languages are "good enough", in an engineering sense, for today's retail features. The payoff of using a fast language doesn't provide enough value for its cost. It doesn't matter that searching a PHP array is slow; that's not where the problems are in today's software.