I can own an ebook or an MP3, while some services license them many of them actually just sell you the media outright. Why are movies any different?
Otherwise, I agree, if we're (for some legitimate reason) forced into licensing instead of purchasing, the license needs to be perpetual and irrevocable.
That's not accurate. Go buy an MP3 from Bandcamp, you own the mp3 (it's a merchandise transaction, not a license, it's very explicit in the terms of service) -- you don't own a license to the mp3, you own the actual mp3 (same as you would own a CD). The same is true of several other mp3 stores and a handful of ebook providers, as well as when you buy ebooks directly from the author (quick example: https://melissafmiller.com/how-and-why-to-buy-ebooks-direct-from-me-and-other-authors/).
Owning the CD doesn't allow you to make derivative works as owning the CD doesn't make you the copyright holder, just like owning the mp3 doesn't actually mean you're the copyright holder, and I'm not making any argument otherwise (referring to your "legally permitted to do whatever you want" comment) -- but you absolutely can buy mp3s and ebooks and not license them.
DRM is an entirely separate issue and not relevant here as none of what I'm referring to relates to non-DRM protected licensed content.