This is an excellent line of reasoning.

PL research just hasn't had much affect at all on mainstream programming.

It's too bad. The PL world has a lot of good ideas. It's unfortunate they try to make them totally inaccessible.

Worse still that industry has no interest in raiding the PL world. A lot of the languages that have been designed are perfectly usable by mere mortals and a real step up from languages coming out of industry.

Compare OCaml and Java in 1996. OCaml (then Caml Special Light) was clearly the better language. Why didn't anyone get to use it?