Not going to happen. As bitcoin gets more expensive, altcoins will provide the supply needed for the utility of bitcoin (doing business) which will reduce the demand and thus price of bitcoin.
Newcomers to crypto-currency aren't going to want to be part of a system where a select few have incredible wealth, hence why they will opt for altcoins instead of bitcoin.
umm except no one takes altcoins?
Not only that, but I don't think that's true anyway. Look at Litecoin. A quick google search for an LTC rich list shows that about 80% of the coins are held in about 1% of the addresses. Pretty much all successful coins are going to have this kind of distribution because you always have a few early adopters that get most of the coins while the diff is still insanely low.