You can't provide a seamless UX for turning on the TV and watching The Office if you don't own the rights to The Office. They want to habituate you to scrolling through content Netflix actually owns and picking something, because it's apocalyptic for them if you ever treat the services as fungible content libraries that you hop between month-to-month.
A short while ago, I noticed I only used Netflix to watch 2 classic comfort shows, and I started to doubt if it was worth a 2-classic-comfort-shows-as-a-service subscription. I tried looking through the catalog to see what else I was paying for and ended up cancelling my subscription.
Netflix does an amazing job in giving the impression that they have an endless library of top quality content, but in reality, it seems like it's only a handful good shows and some filler, but presented in a way that makes it look like there's way more than it actually is.
Whenever I physically can I buy DVDs or digital downloads.
I guess I just didn't understand the Netflix model - why would I want to rent something that I can just buy and have for life? Especially with the enshitification these days - it means I have to pay a massive amount of money (over 5 years say), for a shitty experience, ending up having nothing when I cancel the subscription? That's just a recurring bad deal, in my opinion.
So regardless of the state of their content library it's necessary future-proofing.