No Just did the test before posting on my ipad pro to make sure it was still the case. Music + advertisement on Reddit -> no more music (and the same with the autoplay videos on 2 news sites)
On Reddit as you need your finger to scroll and a lot of videos are in the way it's almost impossible to scroll without touching one-> the music will stop.
I’m not saying sound management doesn’t suck on iOS. It does. But the scenario you describe is forbidden by Safari and Chrome on mobile and desktop. Unless I’m misunderstanding something.