I think that Bitcoin will alway be above all other cryptocurrencies. Bitcoin is first cryptocurrency and that gives it a lot. It broke the ice and showed people what cryptocurrency could be or become. Also if it was not the best, it wouldn't have the highest price. Maybe in time it will lose to some other or new crypto, but for now its first.
Yes for now bitcoin is the unstoppable cryptocurrency among all cryptocurrencies. Many people is using bitcoin and a lot of people is now investing with bitcoin. The highest price of bitcoin is one proof that bitcoin is really the best.
I think bitcoin never ever lost its dominance, In fact bitcoin is dominant over all crypto currencies from very beginning and we can expect that it will remain as dominant for ever. Bitcoin is in fact the very first digital currency mainly created for online shopping etc but now we can see that it is even use in local shops for shopping. the shopkeepers interested to accept bitcoin for shopping. The popularity and importance of bitcoin is increasing from time to time, which is making the future of bitcoin more bright.