Could go as high as 80 percent, and if the bitcoin dominance really does reach 80 percent, then the price of altcoin could rise many times if many bull markets come to pass.
It could ONLY go to 80% if Bitcoin continues to tank deep which makes altcoins tank even deeper. Bitcoin going up means altcoins will eat up Bitcoin's market cap dominance and we'll be back hovering within the 40-45% range.
People just need to accept that Bitcoin being even close to 50% is a fantastic achievement with so many altcoins and tokens artificially inflating the total market cap. It's one coin (BTC) versus thousands of other coins. It's an unfair comparison in every shape or form. Bitcoin technically has only a few competitors, while Ethereum has hundreds of competitors trying to take its spot.
Bitcoin gained dominance verus all other coins. Ethereum lost dominance verus all other coins. If there is one coin 'losing' the battle, then it's Ethereum.