I think the PB will stay for a while, I have mine since day one, I'm in Colombia and you don't see that many PlayBooks but every time that I use mine in public it draws attention. The problem is that the discounts that you see in Canada and the USA are nowhere to be seen here and the PB is just as expensive as it was on day one, a price that it's not attractive anymore.
I'm pretty sure that once I get BB10 on my PB it will be good for at least 2 more years!!!