I think you're taking a very narrow definition of what a threat means to make your point. To a Marine in Afghanistan, the threat was not mitigated by a nuclear arsenal. To them, close air support from a technologically inferior aircraft like the A10 did a better job of eliminating a threat than the F22 in many instances. To the original point, this is why it became difficult to retire the old plane despite the JSF and F22. It could be tied to a specific threat, and that meant it was politically much easier to defend keeping it around even if the business case was that it costs too much money. At the end of the day, politically defending a budget is much easier if it can be concretely tied to a credible risk.