In a 2007 article, Russ Cox (at presents, he leads the development of the Go programming language at Google) argues that regex engines in languages like Java, Perl, PHP, Python, Ruby are built on a different theoretical framework from implementations like awk or sed. Cox claims a difference in performance between 60s and 20microseconds (the difference is an order of magnitude of millions!). [Link to the article.](https://swtch.com/%7Ersc/regexp/regexp1.html)

Is this issue still up-to-date? That is, is the theory behind these groups of implementations basically different?

Is there any real life scenario when a programmer would need to pick some Jurassic implementation like awk (due to its solid theoretical framework) because otherwise the task at hand could not be dealt with?