Agree, the market dominance is very high for the Bitcoin and it is impossible for the altcoin to increase. Still, it is a very good chance for the investors to grab some cheap coins altcoin with high potential active developments will help the coin to increase very quickly once the dominance of Bitcoin is going down.
But if eventually the dominance of the price of Bitcoin still does not go down then you will experience a loss in the alt you have bought. Indeed, the dominance of Bitcoin is still strong and we do not know when it will end. I personally still have confidence that the Altcoin season will come soon.
Bitcoin's dominance cannot be higher than 80% when there are so many coins in the cryptocurrency market. It is best to invest in Altcoins right now, the Bitcoin dominance index will drop next year.