Hi!
I am interested in your question and I want to share my thoughts too. The cost of such an app depends on what specific features you want to include in it. I think an app like Netflix should have these features: Live Video Streaming, User Registration, Subscription and Payment, Integrate Social Media, Multiple Device support. The cost of the application also depends on who will develop it. You can hire a freelancer, a team of developers (outsource the development), or assemble your own team. Your team will include the following specialists: Project Manager, Android/iOS Developers, Backend Developer, UX Designer, Quality Analyst, Business Analyst.