Netflix wont be around for many more years. The critical mistake was switching their servers to AWS, you never pay your competitor even if it reduces your costs.
In hindsight, of course it went that way. Have you seen the culture deck?
They've been on AWS forever haven't they? Long before prime video. I very much doubt that it reduces their cost, even at the pricing they must get. It lets them focus their effort.
Ok lastly you're wrong on their longevity. Yes some people will cancel but the vast majority will not, and they will see more revenue. I don't 'get' Netflix (the content sucks and they are like Google -- your favorite show is likely to get canned, simply because the very best shows are almost by definition "uniquely" appealing and TV, er streaming content is too expensive to generate many such shows) but every remote has a NFLX button. In the end there will be netflix and disney.
Imagine being the tivo of streaming.
Instead, they spent too much money hiring too many brilliant but overconfident types. Average people could have done it, at low wages with lots of equity. Saving more money for customer acquisition.
They did a good job with their DVD service, which has a more easily understandable barrier to entry. They thought they had a similar barrier to entry with streaming, perhaps in part due to thinking that what they were doing would be so hard for others to pull off.
Of course, this is all in hindsight, so take it for what it's worth. But, as noted, even back then they had platform examples to model themselves after. Perhaps they weren't going after such kind of dominance, but still they could have foreseen vast competition.
Apple, OTOH, gets it. They can't even give away 1 year free of their TV service. But they will keep plugging away at it. Come to think of it, they are probably netflix's worst enemy, not disney etc. Netflix do recognize this ... they wisely refuse to be a provider on ATV, where they will just get 'amazon'd'. When your competition is Apple, you are in a bad place.