I'd argue that it always held true to a certain extent. You don't necessarily need the underlying knowledge to be an efficient programmer in Python, but knowing C or Assembly certainly gives you an edge when it comes to, well, edge cases.

And it isn't all about efficiency. Programming and CS is such a major part of my life, that I want to know the deeper parts, and I want others to understand it too. Programmers who do not seek that knowledge I unjustly judge for it.