Well the F35 is a plane so advanced it needs heavy maintenance. Recoating of materials and so on. Sometimes just after 1 flight.

So yes, having a shortage of rare earth materials does impact the daily operations of the US Air Force. And that was just one example. But sure, up to you if you consider being able to fly your 5th gen in 2020 is important or not. I'd say yes, it's quite critically important. But you do you.

Secondly, if China cuts off our supply tomorrow, we won't be able to replace it just overnight. For one we don't have the technological expertise, because we haven't extracted them before in the difficult conditions it's done. So you'd need to develop expertise, infrastructures and so on. Which takes some years. Cutting off rare earth supply to the US would in effect cripple critical parts of the US armed forces for a significant portion of time. And that vulnerability is unacceptable.

Thirdly, don't be so optimistic in your legislative perceptions. It's not a given, that oh if we need it we'll just make it legal and so on. Just look how long the dispute of that gogdamn pipeline to alaska or whatever, took. Years of legal back and forth. Also, no one can predict the political landscape of tomorrow. We could see a democratic majority government where the environmental impact of allowing extraction becomes such a sensitive issue for their base that they disallow it. Just as we could see a ban on fracking. It's not far fetched. France for one has banned fracking.