I stopped reading when a post in 2017 compared anything to perl 5.8.7 which is older than what CentOS 5 shipped.

Perl 5.8.x was EOL in 2008. 5.10 was EOL in 2009.

The currently maintained versions are 5.22.3 and 5.24.1 and major redesign, refactoring, and rework has been done in the system including the regex parser. It went in the meantime from being a primarily recursive, backtracking NFA to using a DFA when possible, being primarily iterative, and only recursing when necessary.

Anyone intentionally picking a more than decade old version whose major version line was end-of-life nearly a decade ago to compare to their new hotness has completely invalidated the evidence for their arguments. All the great things the slides might say may still be true, but they are unsupported by these charts.