You can work around the Widevine issues by pirating the content you're interested in.
Most people will not use a browser that can't open youtube videos and they know and exploit this with extreme precision.
You're already paying the monthly fee to stream it, you're just streaming it in a more friendly way. Granted if you cancel the service, you should delete the content.
Many won't though and that's the problem but that problem is caused by the fact that you're being restricted in the first place.
Nothing is stopping you from buying a 4k webcam and recording your computer monitor
Video DRM that doesn't protect the stream all the way through to a decryption key embedded in your eyeballs always seemed somewhat futile to me.