I'm using Bitcoin-qt on Mac and it's been a few weeks since I last fired it up, so it's doing a sync. I've waited a few hours now, despite being on powerful hardware and a fibre connection to the web.

If I understand it correctly, the sync involves some processing for every Bitcoin transaction performed globally. In the bright future of Bitcoin, when people are buying Mars bars with them, won't the sync be prohibitively slow due to sheer volume?

Or are we hoping Moore's law will offset this growth?