It was interesting to hear Dan talking about what brought him into the blockchain space in the first place (Ron Paul and all that), I think this has allot to do with why he left Steem and what he meant when he said it was broken. I always suspected that Dan was actively involved in making Steemit have a very certain political stance up to that point ( namely alt.right ). I imagine that he and Ned did not see things eye to eye in this respect and this is why he left. I don’t think he meant to say that Steem is broken from a technological perspective.
Also, Dan is clearly a novelty seeker who loses interest in projects once they reach a certain maturity level. So maybe his decision to move along is actually a proof of maturity for Steem. Things have changed a lot here since he left ( Gosh, it is hard to believe that that was only less than a year ago ), and I think it was only for the better.
Having said all that, I also have to say think Dan Larimer is one of the most brilliant minds of the blockchain arena today. I trust his calls and I believe EOS is going to be a great success.