Justification: the 1MB block size limit and the fact that the price has pretty much grown hand in hand with the number of transactions per block (in the long time trend). We have free transactions now (for old enough coins). Eventually a minimum transaction fee for ANY transaction will be several dollars, when the block space scarcity really starts to constrict usage. If BTC adoption grows at the current rate, in a couple of years this scenario is going to be real. This will mean, by the way, that the block subsidy will be insignificant far sooner than most people think. At 20,000 tx/block and $1 fee per tx, assuming $400/BTC and current reward level, fees will be two thirds of total miner revenue.
I do not expect doing away with the block size limit until we've seen its economic consequences. Many influential people have gotten stuck in early 2011 and the "everyone must be able to run a full node in their cell phone" mindset.
+1, mp420 summarized my thinking exactly.
$400 is the most we will get until the block limit is made flexible or removed. The fear-mongering about nodes disappearing (centralization) is not shown with recent stats, which identify up to 350,000 active nodes.
http://bitnodes.io/
Many more than two years ago when it was more like 20,000