Let me direct your attention to page 3.
allow me to direct your attention to the dictionary:
http://dictionary.reference.com/browse/gold+rush"a large-scale migration of people to a territory where gold has been found"
next i show a chart:
see that little jump from may to july? that happened because those mining from april to june were making money like crazy, and others rushed in as they wanted a piece of it too. that's the bitcoin gold rush era.
it matters not to a miner that block rewards occur at a fixed, predetermined rate and doesn't change (at least not significantly) regardless of how many miners there are. to a miner it matters only that the price is high enough and the difficulty is low enough so that buying electrons and sending them through the gpu gauntlet results in profit.
when that profit is large, a gold rush follows.
when that profit is small, or cannot be obtained, the boom goes bust.
the block reward concept serves two purposes. it bootstraps the currency and also is the incentive to get miners participating so that attaining 51% would be something very difficult. the fact that some miners who happen to have been lucky on their timing gained a nice bit of wealth as a result is not a concern, or flaw, for bitcoin.
but there's a 50% drop in daily btc generation coming -- that's a fact. whether or not we are still in a boom is depends on individual factors but the squeeze from the upcoming drop to 25 btc will cause many miners to see it as a bust.