There's already a good solution to buying and owning digital media: you pay money to download files that are playable offline.

When you pay for content locked to a platform, you're not buying an asset, you're paying for a service. The platforms grow around not only providing a convenient service to the end user, but also to the content creators, who publish on them with the expectation that their content is protected by DRM. Creators are free to choose where they publish, and end users are free to choose which services they use.

I don't think it makes sense for the government to define what it means to own a digital asset or to force every service platform to become a retailer and ownership-tracker. Where there's demand for DRM-free downloads or physical media, the market will respond.