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.
The best part about bitcoin is that even after having a small market cap, facing china's ban and constant volatility, it was able to hold and increase value in such a short span. Cryptocurrencies as a whole is developing as well. It didn't have a downfall as such it's just become more popular.
Those were very small issues compared to the large volume hacks and the negativity spreading. Some form of FUD gets around the network to make it down and support the growth of another token. In my personal thinking bitcoin doesn't seems regaining dominance, because it never gave up its domination on the cryptocurrency network.