Were native. About 500 years ago. Ecosystems change. Bears and wolves were also native to Scotland once but we'd think twice about reintroducing them.

Why think twice? There are many many large predators in the US and we get along fine. The US outside of Alaska has thousands of wolves, 10's of thousands of mountain lions, 100's of thousands of bears, millions of crocodiles, millions of coyotes, etc... no major problems. And they're not just in the sparsely inhabited west, densely populated north-east states like NY, PA, NJ, MA, CT ,etc. have thousands of bears and coyotes (though admittedly not many wolves).

My dad's back yard has a view of Lake Superior. A couple of times he has seen a black bear wander through his back yard, and he occasionally sees a wolf stalking some deer in his back yard.

He doesn't have a dog, but some of his neighbors sometimes have their dogs cower up to their owners during walks because they smell wolves. Supposedly some people have seen wolves stalking their dogs, but I haven't heard of dogs being killed by wolves in the area.

It's mostly safe for adults, but I wouldn't let a kid run around alone in my dad's yard, mostly for fear of the rapidly flowing small river, but also due to wolves and bears.

In the US several regions have reintroduced or supported nearly extinct populations of wolves.

There are alive trees in UK that are more than 500 years old. Think about it.

I have thought about it — on your advice — and it is entirely unclear what the actual point you’re making is