If BTC reach 1M percoin is mean the market cap about $19T. I think this is very possible will happen in the long term, because Gold market cap currently about $11T. And currently less than 5% of people in the world know and understand about Bitcoin, and day by day alot of more people will interesting about it, just like increasing of Internet users.
The likelihood of bitcoin having an increased market cap is very possible.
There are a lot of experts that have said that this is still about to mature and we're just seeing it grow with the adoption that goes with the institutions.
Having that and with the government making rules in favor of bitcoin, we just have to wait until bitcoin reaches and surpass higher prices that we saw this year.