It's shorthand for an end result that is in practice similar. If I fork the project, add new features, and license my new code under the GPL, a user of the forked version needs to abide by the copyleft provisions. They could, of course, continue to use the original Apache v2 code without my GPL'd additions, on a non-copyleft basis, since I cannot relicense the existing code.

You can make a derivative that also includes GPL parts, and the entire package will be GPL for practical purposes.

Yeah, but you can do a simple change and suddenly it's derivative and you can licence it as GPL.