This would result in a market cap of over 1 quadrillion (which comes after trillion). I do not see that happening in the next 20 years. Imo, before Bitcoin would get close to that price, we would likely have found a new way of valuing it other than the USD. Ideally in a couple of decades Bitcoin's value would not be solely determined by some other currency or asset.

This is a more realistic target for the next 10-20 years.