In as simple terms as possible: The two main value propositions of Steem are that it is a decentralized and censorship-resistant social media network. The current (old) Steem blockchain now is neither decentralized* nor censorship-resistant**, while Hive is.

For someone who doesn't care about a social media network being centralized or having censorship, Steem wasn't the place to begin with. You could always reach a wider audience and make more money on the mainstream social media networks. And for the people who do care about decentralization and censorship, they are going to drop Steem like a hot potato now.

*Steem is not decentralized now because Justin Sun is running at least 20 puppet witnesses (presumably even from a single server) to centralize the blockchain governance under his control and voting for them with the Steemit, Inc stake. The Steemit, Inc stake is removed from the Hive fork.

**Steem is not censorship-resistant now because the steemit.com front end is in fact currently censoring posts. They even added an external black list source in China that they can add posts to censor without even having to change the GITHUB code now.