Dominance isn't always proportional to market cap directly. It is by no means concrete, as bitcoin's interest has dipped in times of stress before. The question now, however, is what make of such downtrend.
The thing is, at the beginning of every year, the dominance percentage downtrends. Its nothing to worry about.
What surprised me was the number of nodes @BTC versus ETH (for example). Ethereum has 4 times more nodes than Bitcoin.
Near term BTC will struggle given the high transaction fee.
Number of nodes doesn't qualify the reason behind this downtrend. Bitcoin will obviously have lesser nodes than other cryptos since it has the largest blockchain of all time and selective few wants to run full node.
I don't believe that if BTC will plunge massive, then the entire crypto market will go extinct. There is too much money and people who needs cryptos.
Bitcoin is the backbone of all cryptocurrencies. It won't fall ever.