Even if an altcoin has better features, Bitcoin still has the most secure Blockchain, has the most liquidity, and has the biggest network effect. A currency is only as good as the people who use it and being able to exchange it for goods and services or even other currencies/assets is an important aspect of any good money.

Think of it like a social media network. Facebook is a dominant social media company and anyone could make a new and better social network, but any new network is basically useless if there aren't any people to use it, regardless of how good the features are.