If you have a portfolio with:

- 20% allocation to Bitcoin   

- 80% allocation to S&P 500

And you don't touch the portfolio again for 20 years (no money in or out)

Bitcoin: Let's use a 35% return for the next 10 years then 30% for the following 10

S&P 500: Let's use a 7% return for the next 20 years

At the end of 20 years, your portfolio will be 95.4% Bitcoin, 4.6% stocks