Love or hate your leader(s), I think it's hard to place the blame on them. A leader of a country is only as good as his cabinet/advisors. In New Zealand's case, it was a case of "size matters". Where, in this instance, smaller was better. Add in the fact that access to the country can be controlled pretty well. Y'all have 5.1-ish million people. California, alone, has eight times that, and open borders. And, you know us, "nobody's going to tell me what to do". . . . whereas your citizens knew what was good for them, and did it.
When this first started, and people here had at least a little fear of it, we were doing what was right, and the numbers were dropping. Texas was below 5% infection rate, and dropping. But, Memorial Day arrived, signaling summer was here. Even then we got the surge going back down, and then. . . . Labor Day, and some more business started back up. . . . and it was out of control from there. Without the vax, everybody in the U.S. will get it sooner or later, because
you're not going to tell us what to do.