Given that the cryptocurrenct money is presently always and quickly building up, the prevailing digital money will be one that will have great usefulness, accommodation and convenience. Furthermore, barely the name of the digital money will have a conclusive criticalness in this regard for quite a while. Consequently, if bitcoin does not dispense with the inadequacies in it and won't be always enhanced, it will rapidly lose its prominence and request, which will prompt a drop in its cost and about the overwhelming position is not feasible.
I think because ether will always have a much larger inventory, and it should work as a platform for technology companies, and now people are even talking that it could find the place as a "bonding simulator". If you've ever done this, and attacked Wall Strees, then the market cap will be greater than BTC.
If you consider only marketcap dominance, then I do not know. Perhaps in the long run it will be, because if it succeeds as a global currency, it will require a large market capitalization, but in the short term, I think that ethereum might swap places with BTC.