We all know that owing 21 bitcoins doesn't make anyone a millionaire. At today $1300, one would need 760.23076923 bitcoins.
The fact that people keep thinking about it terms of being a "millionaire" is a clever way to make people feel good about their 20 or less bitcoins. If you all want to become millionaires get out there and earn you money, and then buy bitcoin with it!
What's he's trying to insinuate is that there are millions of dollars to be made and in the future there will be 21 millionaires made from Bitcoin due to increasing value and... well, whatever else he thinks is going to happen.
He's not saying that people right now with just one Bitcoin are millionaires, but that people "to become millionaires" are currently alive. or something like that. I'm guessing.