This article jumps to a TON of conclusions, but it gets a couple of basic details right.
Disney alone isn't the problem for Netflix. The problem is that now, ALL the heavy hitters are talking about having their own streaming service out there. WarnerMedia has already let all other services know that when their service launches, either their content becomes exclusive, or these other platforms need to prepare to deal with delayed availability or increased fees. That becomes part of another problem, but I'll get to that.
The talk of Disney launching blockbuster releases day and date on + alongside theatrical is absolutely fukking absurd. The minute they do that, major chains like AMC and Harkins are at their neck to renegotiate what they're paying to run their films. It would be a textbook instance of cutting off your nose to spite your face.
But ultimately, Netflix's problem is that only their original content will be what truly drives subscriptions. They've known this for a long while, and have been attempting to prepare by buying rights to everything they can, and working those purchases into their suggestions. The cost of investing in content and paying to keep their catalog of third party shows and whatnot is what's been driving cost up (I'm looking at what I'm paying for the 4k capable plan, and it's nuts). Ultimately, Netflix will be ok, but to survive long term, they'll need to take a look at actually lowering prices if their catalog ends up losing a lot of the big name old content that drove costs up. Otherwise, it's a matter of time before the wave of people discovering that they don't actually like Netflix's content becomes a problem.
That, or they get themselves acquired by AT&T or Disney. Actually, that's probably the most likely conclusion