Yes. There are a couple of threads elsewhere in the html subforum about the changing definition of "standards". In the past there was HTML2, HTML3, HTML4. In the future there will be HTML and-that's-all.
The dtd shouldn't have a huge effect on the browser's behavior in any case. All of mine are perfectly happy to handle <wbr> in documents marked HTML 4-- so long as I don't try to validate. (The validator doesn't know that you've used an html5 construct. It only knows that it isn't html4. You could have said <xyzzy> for all it cares.)