I wonder though how much of it is "new" revenue as opposed to cannibalised revenue from other mediums. Sure the figures sound good on paper but how much of it is offset by the loss of license revenue (as Disney pulled their content from other platforms) and lowed DVD/Bluray sales as people use the streaming service instead.
I suspect their back catalogue will be enough to keep many people subscribing on its own but as Netflix has shown producing content on the scale needed for a popular online streaming service is relentless and eye wateringly expensive.
For it to work long term, its going to need more than a few Marvel TV shows and Star Wars Shows. It will need an ongoing and ever growing catalogue to keep people entertained. The only thing I can think they are hoping for is that Disney+ is priced at such a price point that it will be the 2nd or 3rd service you own, so you get the likes of Witcher etc via Netflix, others via Amazon/or other provider then your Star Wars, Pixar etc from them...I currently cant see this being your sole subscription TV service.