Well yeah, they should. They have the largest install base of any streaming platform by quite a bit by virtue of being the original big dog. But that isn't relevant to why they're now hemmoraging subscribers, leadership is freaking out very publicly, and why their stock is tanking.
But even with that said, put no stock in any numbers anyone reports for streaming "ratings". The truth is only the streaming companies know how many people are watching their stuff and for how long, and they heavily manipulate that data when they make it public (Netflix will tell you 40 million people watched something when they mean 40 million people watched two minutes of it.). All third party organizations are using voodoo methods to arrive at their numbers for streaming. Even Nielsen.
Going back to my earlier post, lots of creators on the animation side of things have said they found it impossible to get actual accurate data about who was watching and for how long from Netflix. If the people who make it are in the dark, I assure you no third party company is all that accurate.