Right exactly. The only way IP blocks work is if there's no vulnerable machines to take over anywhere. That is - it basically doesn't work for any motivated a

Right exactly. The only way IP blocks work is if there's no vulnerable machines to take over anywhere. That is - it basically doesn't work for any motivated attacker. You could hypothetically make it work, but it would mean an extremely different Internet and device landscape than exists today. (And even then I doubt it stops a nation-state level attacker, they can always use old fashioned espionage to get someone in meat space and get around any technical barrier)