Above the answer list, there's three tabs: *active* (descending by change), *oldest* (ascending by age), and *votes*, the last one being the default when you haven't changed the order.

In all of these sort modes, the accepted answer is first *only if not by the same user as the question*.

So your request is actually the default, and (AFAIK) has been from the beginning. Open a private browsing tab to get rid of your cookies and [see for yourself](https://i.sstatic.net/8SHV9.png).