The moat is the leverage to get licensing deals using the size of the existing user base.
You could bootstrap a movie rental business by buying DVDs from a DVD store (then eventually from a DVD distributor, etc.). You cannot bootstrap a movie streaming business by buying streaming rights because nobody will sell them to you. They hardly even sell them to Netflix anymore.
The Internet Archive tried to get around the same issue for ebooks by scanning physical books and renting the scans (and not being a business), and it nearly cost them everything.
Netflix doesn't have the moat of "built a physical wire connection to every persons home" that cable TV enjoyed.