I understand the sentiment, but to be fair, CGI doesn’t give you an infinite scalability. AWS Labmda based solution is far less susceptible to something like HN hug-of-death.
This maybe gets to the core of why the author’s assertion is incorrect: they’re comparing a programming language to an execution environment.
Yeah, PHP can scale infinitely… if you provide it with the necessary server resources to do so. PHP is not going to scale infinitely on a Raspberry Pi.
This dynamically scaling server resource is Lambda. Hell, you can even run PHP on Lambda these days the comparison really doesn’t work.