Shot, trapped, poisoned (basically nothing was illegal or off the table), and all with a bounty system in place to incentivize everyone to actively kill them.Shooting them out of existence is exactly why they are not in Colorado. They were literally shot out of existence.
They've done studies in Canada which show that if you put enough hunting pressure on wolves, they will basically go nocturnal to the point that you won't see them during daylight. This alone disproves your point about hunting them out of existence. It also shows how a longer season can actually be less effective than easing off and letting them settle down again