A possession change should count with a successful punt. This was an unsuccessful one, and should therefore be treated like a fake punt. You can keep the ball if you advance past the first down marker. If you don't, you can't. I don't think they should view a successful punt and a blocked punt the same way.
In the end, it won't be for us fans to decide. Since Jerry is now interested in this, the league will probably debate it in the offseason. Of course, that doesn't guarantee a rule change. They may or may not change it. If they do change it, they may or may not consider the first down marker -- or they may just whistle the play dead if the kicking team touches the blocked punt. I don't see that much point in arguing it further here. It's the league that will decide what to do, if anything.