I had this experience leaving the Apple walled garden about six years ago and moving on to Ubuntu (with Windows for gaming purposes in free time). I just kind of ate the costs. I suppose technically I still have access to my video content purchased on iTunes, but I'd have to boot to Windows or use a VM to get to it.

My rationale was kind of along the lines of avoiding the sunk cost fallacy: just because I'd been invested in the Apple ecosystem for 20-some years and buying iTunes stuff for more than half a decade didn't mean that I should just keep doing that when I was unhappy with other things. But that cost-benefit calculus might work out differently for other people. The lock-in is very real if you don't want to lose your stuff. It's a reason that I still refuse to buy movies from any online service. Only discs that I can rip or DRM free downloads for me from now on, so I don't end up walled-in again.

Eventually I was able to rescue all my protected music at least by paying what ammounted to a $25 ransom for a year of iTunes Match (or whatever they call it now) so I could download DRM free versions of the music I'd already paid for.