I think bitcoin reaching a million is unlikely
It would value satoshis too much and by that point, there would need to be other divisions to split up even satoshis.
Transaction fees would also need to be changed as by that point people would be paying hundreds of dollars for each transaction.
Basically, In order for bitcoin to reach a million, there needs to be a lot more services around to assist in the sending and receiving of bitcoin as well as the actual workings of bitcoin