Think about it - music production, video editing, photo editing, graphic design, coding.. These are all things which used to be considered extremely difficult but have now been made easier with fantastic, accessible software. Huge amounts of specialist hardware are no longer necessary or indeed desirable in these fields and the new MacBook Pro recognises this - software development (and other areas) are moving increasingly to the cloud and a huge development machine is no longer a necessity..
I'd suspect that Apple sees the future of its products and services in the cloud and the machines it provides will be slightly different gateways to that future.