This will happen if the USD losses so much value that it actually becomes hyperinflated fiat garbage. Still for hyperinflation to occur in the US we must see dramatic geopolitical changes, embargo's vs the US, real war or economic war that affects the population, or total mismanagement of the US assets along with economic war. Governments believe in printing fiat to solve all their problems and as we've seen in history this is what always happens in extreme situations. Although I give almost 0% chance for this to happen for at least another 50 years. If this happens there would be no point in discussing BTC/USD terms.

Also there is a possibility that Bitcoin actually grows huge in popularity and mass adoption levels reach so high that everyone is using it for their daily transactions. This is what will bring Bitcoin to 1m USD and I think we have a high chance in achieving this in the next 10 years.

I remember promoters of Bitcoin and topics that I was following since 2013 that were laughing with predictions about Bitcoin reaching 10K. So it is always better to keep an open mind and not exclude this possibility.