Who says it's effective? The pirate streams still go up every game, as far as people report here. They can just change their ips or hosts occasionally.

It's the honest businesses who probably won't go through the effort of evading the block every time.

Also, clients of the streaming sites are quick to find and spread workarounds, mainly VPNs. But the small shop in the same IP selling to middle/older aged lose business and look unreliable to their clients, that can't even spell VPN.