This writer is a little too "rah rah" about the subject, especially given his unconvincing assumptions.
He presumes that Netflix will see a crippling loss of subscribers when Disney+ launches, as though there is only room for one of the two platforms in a home. Netflix's relative dominance doesn't seem to be pushing Hulu towards collapse. HBOGO and HBONOW are still doing fine.
Will there be switchers? Sure. But you know who else will lose a ton of (and possibly more) subscribers when Disney+ launches? Cable. That's another big pool of people for Netflix to pull from. Will the people dropping a $50/month cable subscription have any problem picking up Netflix and Disney+ at less than $20/month total?
Disney has great content but I can't imagine choosing to watch it exclusively, without other options. I'll be subscribing for sure... On top of my subscriptions to Netflix, Prime, Hulu, HBO and DirecTV Now.