move to another assest
like what, dead people printed on pieces of paper? that sure sounds more stable long-term

see, when bitcoin reaches five digits it will be the thing that you sell other things for. you don't now say "if USD reaches 0.02btc, I'll sell all my USD and move to another asset", same way you won't consider your bitcoins as something you need to "sell" - they will be your currency.
He said asset, not cash. I can think of some assets that are reliable and perform much better than the USD:
-Futures/commodities
-Real estate
-Real estate investment trusts
-Blue chip stocks
-Bonds
-Small diversified positions of precious metals
-Guns
You shouldn't have all your eggs in one basket, no matter how bullish you are about the basket. Bitcoin becoming a serious world currency and that is infallible is just a speculation, not a guarantee.