The more money there is in bitcoin (i mean as the price of bitcoin goes up), the more motivations that there are for scammers to figure out ways to exploit various weaknesses in bitcoin (whether that is taking transactions off the blockchain or some other schemes to obtain the bitcoins of others).
You mean like all the ASIC companies and the thousands of miners who got robbed blind by pre-order scams? How about the half a billion dollars in coins Empty Gox made disappear? First Pirate Savings & Trust?
There are a lot of examples, and yes, you are correct that examples go back to times in which bitcoins were NOT worth very much - however, many of us must admit that there has been increased awareness and security measures for securing bitcoins - nonetheless, my main point(s) seems to be that incentives to employ various scandals goes up as the value of BTC goes up - yet, even if the value is low, there still could be opportunity to engage in scandals.