600k per coin would equal $13T market cap, which is almost twice the market cap of gold itself.
Not impossible, but it will definitely take longer than 2 years. Every time the market goes up a lot, early hodlers will tend to sell some of their holdings, bringing the market down again.
Remember a scenario of USD/EUR/GBP/etc devaluations. That could make 1 BTC worth over a million USD (and at the same time, market cap of gold will increase too). I see it before 2030, when basket of goods are priced in BTC or the leading crypto of the time.