In your example, getting a third party to provide a digital copy of a good you already own is not theft. I would argue it's a lousy way of doing things, opening you up to many more problems, but it's not theft.
Taking a good or service that you don't own is stealing. That's piracy. That's theft.
I recently went over my media collection and did some conservative guesstimation of my spending over the last 20 years. I've paid over 6 figures to consume various sorts of media.
I have absolutely zero moral or ethical qualms with downloading and/or pirating content I've already paid for. I don't give a flying fuck if the copyright holder doesn't like the means by which I get the content. The studios and copyright lobby and mafiaa are not good faith operators.
Piracy is not theft. Sometimes it's ethical and justified.
I WANT to pay. I want to give a streaming service money to curate, deliver, and maintain a library of high quality content. The industry doesn't want that to be possible, because it interferes with the bad-faith rentseeking games played with royalties and residuals. I'm done playing pretend, and will happily Pirate even new content I haven't paid for.
I will pay when there's the opportunity for good faith commerce. I'll buy discs and files directly where possible.