Earlier quoted context omitted.
Lots of Bitcoin simply get lost and people are betting on this loss too. You are also forgetting the ultimate irony behind long term deflation. At some point your Bitcoin will be worth millions in dollars but will the dollar actually buy you that much product or service if there aren't enough young people to take care of everything?
The endgame is that there will be no dollars and Bitcoins will cover all exchange and savings needs. At that point deflation stops.
Not unless all economic growth stops, too. More people in the world + fixed number of bitcoins = deflation. More cars/computers/thingys made + fixed number of bitcoins = deflation.