When Sony rebuilt Sound Forge for Mac, it started at 1.0 again so if Sony where to rebuild Vegas Pro for Mac my guess would be that they would call it 1.0 again and not 13.
Of course, no one can answer your seemingly "simple" question except Sony. ;-)
I'm hoping the answer is "yes" of course since Vegas Pro is currently the only reason I still have a Windows PC around (the rest have been converted to Mac).
looking at apples support for their desktop / power users in recent years i'd be wondering how much longer they'd be supporting (or at least seriously developing) such hardware when their main income stream (and huge profits) derive from mobiles and tablets.
that said, you can always run vegas on a mac, it's pretty much the same hardware after all. as for rewriting vegas for mac, why? do you think it'd be bug free ;-)
There is only two possibilities for response - "yes" or "no"
The real answer is that nobody on this forum has any clue. If they do know, then they are under non disclosure. If they violate ND then they would never get to play with early knowledge ever again.
Mattel is bringing back their BarbiePC and that is a priority now. Sony knows it will have more users than Macs and Mattel promises to really, really test their stuff.
To quote Morgan Freeman ( he's apparently been very busy saying all kinds of stuff on the internetz about a lot of things )
"Apple is iPod, iPhone, iPad consumer devices company, their "PRO" line is still just what it always has been; Bull$hit. Makes no sense to waste time developing serious software for OSX"