It's not even really that archaic- concatenative languages just never hit mainstream among programmers. PostScript has built-in datatypes for dictionaries and lists, first-class procedures, closure-like mechanisms, clean, uniform syntax... refreshingly modern for something designed in 1982. I wrote a Forth compiler and VM in PostScript a while back: https://github.com/JohnEarnest/Four.Ps/blob/master/four.ps