I like your holy trinity quip. :)

It's interesting that most people acknowledge that each of these languages have some novel insight into program development and yet they tend to be not part of the mainstream.

Is it because the concepts they introduced where just migrated into existing languages and sub-systems? Functions, lists, OOP and stack based virtual machines are common place now.

I don't think there is a VM in the mainstream that uses the Data/Return stack Forth architecture but I could be wrong.