Absolutely: what I should have said is that I've been the one to cause performance problems, I've been the one to solve them, I've been the manager who refused to allocate time to them because they were not important enough, and I've been the product owner who made the call to spend eng hours on them because they were. There are many systemic reasons why this stuff does not get fixed and it's not always "they code like crap", though sometimes that is a correct assessment.

But show me a codebase that doesn't have at least a factor of 2 improvement somewhere and does not serve at least 100 million users (at which point any perf gain is worthwhile), and I'll show you a team that is being mismanaged by someone who cares more about tech than user experience.