But if it happens, and all this rally ends, then bitcoin would not be the same as it was before.
It's not possible in todays market sure but over the years bitcoins volatility will decrease as it becomes more established in our society, once that is the case it will be less than the 20% they talk of.
You must now that 80% of the people who have introduced themselves in bitcoin are because they want to earn money, they do not want to leave the banks and leave a new like with this kind of money.
When they see that they are not earning money anymore, they will leave the system.
But maybe you are right, we need a more stable blockchain, that would be great, not just for the investors and for those who wanna buy, it would be great for the whole system, and for the miners, because it could make transactions go faster than now.