Google's IPO was what, $80/share? By that logic, who in their right mind would buy it at $600?
It doesn't matter how much a stock has already "gone up", they all have to start somewhere. If you want to keep talking about how this went up 1000% you could say the same at 1/4 of the price "Well it's already gone up 250%, dunno who buys it here" .... and miss the chance to turn $10,000 into $40,000 on that leg of the run alone.