There are many broadcasting laws worldwide, many quite archaic. Even Radio Garden got meaningfully restricted in the UK (only licensed national radio stations are allowed by a high court ruling). I worry for projects like TV Garden but they are undoubtedly very cool.

Why not? Public broadcast TV stations want to be viewed, just like web radio streams!

That said, the first one I tried (a German public broadcaster) was showing a static image of “this programme is currently unavailable for legal reasons”. (I believe they do IP-based geofencing for legal/broadcasting rights reasons.)