A couple of comments. Firstly, there is a world of difference (literally) between an international Sevens competition comprising national teams, compared with a domestic Nines event based upon one country's franchises.
The Nines will start with a bang. Maybe it will do okay for a year or two, but it will quickly run out of steam. It would probably do better, for longer, if it were based in Australia, which is where most of the supporters are.
Doyle is smart enough to realise this. That is why he is floating the hybrid game option.
However, there is no incentive for the IRB to do anything significant to the Sevens rules, even if it did mean incorporating a new dimension by allowing loig teams to participate (the addition of GB, Australian, and NZ loig teams in the comp would add a lot of interest). Which is not to say that I think the door is necessarily slammed on any kind of rapprochement. Imagine the ratings if there were to be a combined Sevens competition.
Finally, the Sevens does need some sprucing up, IMHO. The time to do that is before it becomes too obvious. But when a team can win a competition without conceding a single point, maybe we need to think about broadening things a bit.