My Verizon plan explicitly limits YouTube video to 1080p. If I paid for a lower plan, it would limit me to 720p.

I have no option to go beyond 1080p, even if I’m on the fastest possible connection.

Of course, if I were to turn on a VPN, I can suddenly stream at any quality my connection can handle.

This is a real world example of what you claim hasn’t happened. And you can verify it yourself by looking at their available plans.