I think that the D'app owners could have a say in whether or not they left with the chain to a new chain or if they forked off a "classic steem" chain and just stuck around, it would be their choice.
The problem is we don't have any answers on what's really happening, just a bunch of speculation from the community and everywhere.. But what we do have is 20 people making decisions for the entire chain.
You say that "steemit is just one platform," but it's kinda a big deal because it's people who write new code and implement most of the changes done to the chain.
Yes, we have a lot of cool extras right now like Dapps and now Communities but we are still waiting for the finalization on codes for real SMT's and other innovation that is owned by steemit! That's kind of a big deal.
Maybe, because of this, he decides to delay the SMT release until he moves it to a tron network now.. There may be a shit ton of backlash from this and we all might suffer because some people decided to jump the gun and speculate we encountered a worst-case scenario, when that might not have been the case at all. No one knows for sure. Ultimately this action could be the catalyst of why he ends up moving the chain, or moving it early, or fucking over steem intentionally. Wouldn't that be fucking Ironic?