The Joe Public has to get past this notion of either buying whole bitcoins, or buying nothing (because they say they can't afford it.) We need Joe Public to understand that they can buy $0.09 worth if they want. Or $5 worth. Or $100 worth. It doesn't matter how much you buy, it'll likely appreciate long term no matter what. Quadrupling your money on $2.50 is just the same as quadrupling your money on $2500. As is quadrupling your money on $452.78 worth of bitcoin.
We need the script to change from "I just bought another bitcoin" to "I just bought $655.57 worth of bitcoin."
I think the psychological barrier will be finally broken when a single btc gets back into the 4 digits USD and well into it. Hopefully. By 5 digits, hopefully people won't even care anymore what the exchange rate is.
This is a valid point, however, I think you're forgetting the solution of switching to a standard denomination of mBTC. Some services such as bitcoinity already have. You can see people buying 1mBTC for $0.657. I recently bought 180 mBTC for my girlfriend for $100. This is what we need to gravitate toward.
Andreas Antonopolous touches on the unit bias issue sometimes, but it needs to be taken more seriously. You can start doing your part by referring to your stash of whole bitcoins in mBTC.
Pretend you own 8 BTC. Your friend asks how many bitcoin you have. You say, "I have 8,000 mBTC."
800,000,000 satoshi sounds better
If you say it like that then it makes it sound like bitcoin is worth less then it really is.
you make a good point. 50 bn zimbabwe is like 10 usd. maybe mbtc or something is a fair unit which keeps its value