If I rent a car I don’t own it. Is it not stealing to hijack a rental car for a few hours?

Not a great hypothetical. Copying files would mean that in your hypothetical... I see the red civic your rental service is providing... Look at it real hard, poof another one into existence and drive away in it.

Here's my example: I subscribed to Paramount Plus explicitly for Star Trek content. The week I subscribed, they pulled all of the non-Abrams films. So I got to watching other stuff. Eventually, they brought all of the films back. Cool, right?

So I finally get around to Prodigy, a show made for Paramount Plus. Two episodes in, and it vanishes. No announcements or warnings that that show was just going to disappear. It's gone. Because "it wasn't popular enough". A show that only existed on that one platform was pulled off of that platform with absolutely no other legal way to view it. Content that I specifically signed up for that platform to see, and now I can't... legally. Yo ho, yo ho, me hardies.

Agreed. I'm under no delusions, when I pirate media I'm stealing. I personally don't believe it's immoral to steal from super corporations, especially considering how much they steal from us, but some people disagree and with these types of moral arguments there isn't a clear right answer. Even still, I think the majority of pirates are willing to pay for software or media when the service is priced well and more convenient than piracy.