With every new token circulating in the market, they should add up some value and have their own share of total dominance by price.
But for some years, we are having an increasing number of new coins and tokens being traded but still bitcoin is increasing it's dominance.
According to coinmarketcap, bitcoin now holds a 42% dominance. i.e. the 42% of total capitalization of cryptocurrencies is that of bitcoin.
How is it possible? Are altcoins failing?
Everything in the crypto market is traded in pair with Bitcoin, that's the reason for it's dominance.
Plus, the fact, that it has first mover advantage which is really huge.