That is why large groups tend to split into smaller groups that have common interest, understanding and values in accordance to which they measure at their level of being an expert. If Steemit as social experiment survives, with the upcoming SMT's new professional communities will be created like Reddit subredits and they will continue to strive with upvote/downvote mechanism as they will have one commom interest lets say photography that has certain generally accepted standards in that society or ecosystem if you will. In which case steemit may get an empty and desolated space just because of the reason you have mentioned before.

Hence the underlying value is not steemit itself but steem blockhchain that will power up all those communities through different SMT's.