[jasonwatkinspdx]

The situation is a bit more complex than that. We don't know the yield of NK's weapons based on the tests, because it's likely the tests have been sized to minimize material usage and just confirm the physics. Given that they're expanding their uranium mining it seems likely they have centrifuges operating and they're building hybrid bombs. This is the same path China went down when they were material limited.

So anyhow, it's not like a footrace where the major nuclear powers are at the finish line and NK is trying to catch up. They're following their own path appropriate for the situation they're in.