It's the other way around really. This "greater fool" system works as long as fresh money comes it to keep pumping the value. At some point you'll run out of "f

It's the other way around really. This "greater fool" system works as long as fresh money comes it to keep pumping the value. At some point you'll run out of "fools" to come in and invest money, at which point the bubble stops expanding. At this point the most anxious investors will start selling their coins, fearing a crash. This in turns causes the value to start dropping and then you have a runaway effect as more and more people want to dump their coin, crashing its value more and more.