The domination of bitcoin in the cryptocurrency market is loosening as investors are seeking to invest in other smaller cryptocurrencies. A large pool of investors is going towards ethereum as it hit 3k yesterday and many are projecting it to hit 10k before the year runs out.
BTC is undoubtedly the hottest cryptocurrency in the world and its market remains strong. But many still want other options and are going for the smaller coins as there are some with very good projections in the near future
I highly doubt that bitcoin's dominance in the crypto market is loosening because even though most of investors are eyeing other small coins, they still put most of their investment in bitcoin. Indeed they are diversifying but on the other hand, they are well aware of how much higher bitcoin can go after witnessing it achieve consecutive ATHs. It will remain on the top till the end regardless of how many new altcoins would appear, they can never replace bitcoin's throne. People have learned a lot after seeing bitcoin recover from the massive dump last 2018 so they will surely pay attention on bitcoin still no matter what.