If someone bought $100 of Bitcoin in 2010 and kept it until now, they would now have around $6 million.
Do you think the same could happen again in the next 7 years? If I now own $500 in Bitcoin could that be worth $1 million+ in the next 7 years? Or is it extremely unlikely for this increase to happen a second time?
That was a huge percentage. You mean that 20 dollars was bought for only $100 in 2010. It is possible that when you invest right now there's also a big chances that your investment will double or triple or even higher than that after 7 years. But the expectation that your profit will be just as the same with 2010-2017, I think it wont happen.
Always remember too, no one knows what will happen in the future. Anything can happen even in one day.