Wait a minute, dtube is leaving steem in a very fundamental way: going forward dtube users will not need a steem account and the token economics will not be mediated by the steem blockchain...I would say that counts as leaving. You can retain the functionality of posting links to steem (which is fine) but how is that going to contribute in creating demand for steem?

This is Dlive all over again (although a soft version of it). Think about it, they had a huge delegation of steem that was used to cover their costs and now they will operate with their own blockchain. I for one will not applaud this. In fact I am going to stop voting on any content that is posted to dtube so that no beneficiary rewards accrue in dtube's favor.