The fact that it's been reasonably (if imperfectly) effective for a very long time and statistically speaking, nobody is really looking forward to a universe in which, say, border or trade disputes turn into nuclear brinkmanship and the risk of proliferation to non-state actors is greatly increased. These agreements exist and continue to exist because the parties find them beneficial. I don't think a bit of ill-conceived smack talk from a Polish PM changes that.