Another mechanism which breaks the above: if a currency system experienced such dramatic appreciation on an ongoing basis and for so long as to convince people it would never end it will be supplemented with other means of exchange and would basically be a store of value and not a means of exchange AT ALL.. So what? Other currencies will be used...
That's my point. Other currencies will be used. You aren't motivated to spend or do anything except hoard when the value of the money is constantly rising. I'm not saying everybody is going to quit their jobs, they'll probably just use a different currency to buy stuff with, like you said. What good is that for bitcoin?
A lot of people here are drunk on the deflationary koolaid because they feel like they are getting richer for doing nothing (and they are, even with the current inflation until 2040) and they love it and want to rationalize it.
There is nothing else to do with bitcoins other than sit on them currently, but them being used as currency is going to be hampered by people saying stuff like "I'm not paying that much for item X, it's worth it for me to wait it out until item X is cheaper". Meanwhile, producer of item X is going broke, and will accept other currencies instead that won't make him go crazy.
Some people get hurt by inflation, the opposite people get hurt by deflation. If you're going to say one is bad, you have to say the other is bad if you want to be impartial. You could also say both are great! (for some people, and opposite people)