If we write HTML that has no content just the head title body and metadata with script and style elements to external style and script is it really a hypertext markup language at that point?

I think I get your meaning, but I'd guess you're referring to libs like React which only deliver a barebones "document" as actual HTML to bootstrap a script-generated page? In that case, you still have to generate & render HTML at some level to do anything useful on a web page.