Cable infrastructure is built different, with multicast streams. All the channels are broadcast on their network at all times to relays all the way up to your neighbourhood, if not your cable box. It’s got dedicated, guaranteed bandwidth. It can’t get overloaded.
With streaming, each user is one connection using one stream worth of bandwidth, so it doesn’t scale too well to millions of viewers. Technically there’s multicast stuff but it only works locally, and I’m sure all those cable companies that are also ISPs aren’t all that interested in making it work either. So for now we have thousands of identical streams crossing the country at the same time hogging bandwidth and competing with everything else using bandwidth.
It’s the same as glxgears but for EGL and Wayland. It tests that OpenGL works.