Netflix has over 180 million subscribers worldwide. That absolutely destroys the numbers of any of the other services right now. The only one even close is Amazon Prime at 112 million and most of them don't even watch shows on Prime.
Could Netflix lose a lot of subscribers over the next 5 years? Sure--though, with the way coronavirus is affecting going to the movies, socializing, and so forth and kind of forcing people to stay home, I think it is more likely that Neflix gains subscribers than lose them. Does Netflix spend enormous loads of money on an overwhelming mass of content and as a result have a somewhat suspect business model? Yes, but even when they are in debt they've got investors buying into them because of how huge their subscription base is.
The reality is that while there is a lot more junk, Netflix also has a greater variety of quality content than any of the other services. There is really no comparison. They are a cultural staple at this point, comedians tell jokes about Netflix, "Netflix and chill" is a thing, everyone at workplaces and schools talk about what shows they are watching on Netflix because everyone has Netflix, so it's something that everyone can share.
I can't speak to how Netflix might adjust their business or production strategies in the coming years, but I am fairly certain they are going to have quite a few "coming years" to work with.
The other services, man, I don't even know. CBS All Access doesn't have a lot going for it right now, I only have it because it came bundled with another subscription I have. It was nice to get to watch Picard, I guess, and I look forward to The Stand, but yeah, I dunno about that one. Apple TV, haven't even been interested at all though Foundation looks kind of cool. HBO Max needs to get things figured out with Roku. It's all a lot and one of the reasons I don't have cable is because I thought it was a waste of money, so I'm not about to go and subscribe to like 6 different services. But Netflix is not one I am going to be canceling any time soon.