Earlier quoted context omitted.
Marketshare? People are happy to pay a single Netflix subscription, and many people already have one. People would be less happy to shell out for yet another subscription, especially for a single kind of content (unless you watch Disney all day, it doesn't make sense to subscribe).
It's highly likely (see what happened with Disney removing content from Netflix) that, as consolidation continues, other major studios will also remove their content from Netflix. Once that happens, Netflix may find it harder to keep people happy to pay their monthly subscription (which is why Ted Sarandos recently stated that 85% of Netflix content spending is going to be on originals https://variety.com/2018/digita…
Disney and Netflix are going to go head to head because, anecdotally speaking, my kids and all their friends watch these two sources primarily (some overlap ie, Moana on Netflix will likely vanish once Disney's streaming solution goes mainstream).
The key here is that Netflix is essentially free due to it's low overall cost, and parents like the non-kid content so the kid content being free (and no upsell) is a big deal - and unlike YT kids, is relatively trustworthy.
Disney will have to compete to either make a generally good Netflix replacement, or somehow dovetail into that model as a "high cost/high value" seperate subscription and edge out all other such services.