All that demonstrates is that interlink between the ISP and other transit providers isn't saturated. By using a VPN you change the routing of your request, you

All that demonstrates is that interlink between the ISP and other transit providers isn't saturated. By using a VPN you change the routing of your request, you don't just mask the endpoint. A VPN'd request that gets carried over a saturated interlink would suck just as much as a non-VPN'd request.