This is such an absurd fallacy that FSF nuts have been using since at least the early 90s.
The GPL does not ensure jack squat. It ensures source code availability as much as the BSDL does.
Consider the following function:
defmodule Jail do
def jls() do
System.cmd "ls", ["-la"], into: IO.stream(:stdio, :line)
end
end
Regardless! of which license that code is released under, that function is now open source, for the entire world to see and use. Period. It is never going away, it's never going to be unavailable. Or locked up. Or "closed". And "closed"? How stupid a statement is that about open source. Look, you cannot close open source! You can use it but the same open source code you are using is still out there and available! You can't make it disappear.
What you CAN do is ADD to that code. It's called adding value.
And that added value code is yours to do with as you wish. Release it open source or not. I don't give a crap, my function is still free, still open source, and still available for anyone to use no matter what you have done with your copy of it.
So don't give me this crap the GPL ensures code "remains free", it doesn't. That is a load of hogwash. And always has been.
The point of the GPL is to force others to release their value added code. To virally infect non free software to become GPL licensed open source code. And before you say "no one forces you to use GPL'ed code", you are right no one does, but then don't also claim your code is free. It's not.
The bottom line is the GPL accomplishes nothing the BSDL does not already accomplish. Except forcing anyone who uses it to license their value added code under the GPL and play by some socialist zealots rules.
The GPL is a one way technology blackhole. It sucks up other code licensed under more liberal/free terms but can't be used by them in reciprocation.
And your last statement is classic GPL thinking! "Play by MY rules or I am taking my ball and going home!" How freedom loving. We could all learn to embrace such a wonderful concept of freedom as that.