Sure, but the potential habitat of humans is muchgrea ter than that of polar bears.
That is true. And they must be much less densely populated, because they are not so social. But even so, any species that only has 30,000 members and lives in a relatively limited geographic range must always be at risk of a slight problem causing extinction. Mammoths and Cave Bears, for example, who had been around for quite a long time, and perished at the end of the last ice age.