I'd say its a mix between Technology, Community and Accessibility.
Steem excels on accessibility (it is exceptionally easy to develop application on top of Steem) has a decently large actual user base (hosts many of the biggest dapps out there) and has a decent technology stack (not as good as EOS but better than many others) which give Steem its "value".

The price depends more on "having real use cases for Steem". Most blockchains have closely to no use case besides investing the coin, but the investment and hype for them are strong. Which is what, in my opinion is mostly missing for Steem.

Also, many years of mismanagement also resulted in many people not trusting Steem and Steemit Inc anymore. This year they did a turn around. But gaining trust back is much more difficult than establishing trust at the beginning.