Typically Apple will announce a product, and then that product will ship either immediately or within a few weeks. My prediction is that Apple announces the new MacBook Pro at WWDC, but that they won't ship until the Fall. They've done this before: The Mac Pro, the original iPhone, the Apple Watch, etc. . So yeah... I bet we see the MacBook Pro in a couple weeks, but we won't be able to buy it until the Fall, and it will come with the next version of OS X on it. In terms of their current lineup, I would imagine that they either just leave them for sale until they run out of stock or drop the price slightly.