I'm not buying it. Steemit is very much full of follow 4 follow, bot and spam accounts. I do think we have a higher rate of engagement, but it's not a very big difference.
The real difference is that there's a core of users who are thoroughly invested here. It's a very small number, but that core is very engaged because they're financially and/or ideologically invested in the platform.
Followers are also much better monetised, and incentivized to comment. A single view on YouTube is worth $0.001 to a creator via ads. If a user here has a $0.01 upvote, that's already 10 times as much, and the core users have much more than that.
Thanks for adding to the conversation @demotruk! Especially since we have had different experiences - it's nice to get different perspectives chiming in. I would definitely agree that there are a TON of bots and people who try to play the "follow 4 follow" game...but It seems like they aren't taken very seriously on here. At least that has been my experience.