The US military is actually surprisingly decentralized, with a lot of leeway and authority given directly to NCOs, and officers routinely getting ignored, circumvented, or subjected to malicious compliance if they even order something considered unreasonable, much less illegal. Also see: fragging. Malingering. Mutiny. Desertion. And the worst nightmare - Insider Threat. So much of the military runs purely off of trust, faith, and compliance to words on a page.
You think Don’t Ask Don’t Tell was actually fully complied with? Sentries already fall asleep while at their post, willfully, without needing to have any excuse other than being tired or disliking the watch officer. Roving patrols routinely miss rounds, don’t actually pay attention or inspect anything, and practice what we call “blazing logs”, that is, writing down “all conditions satisfactory” without actually looking at the conditions. Maintenance also gets blazed all the time - technicians just straight up not doing the required maintenance and writing down that they did, substituting unauthorized materials, or half-assing the maintenance. Paperwork just gets “lost”, or never gets signed, never gets filed, never makes it to the intended recipient, just because the admin secretary doesn’t feel like it. Information isn’t entered into a system, including disciplinary or otherwise disqualifying stuff, because the admin or command likes you or needs you.
Purging the upper brass won’t do anything to circumvent or “fix” any of that, it’ll make it worse, because it’ll incentivize the servicemembers to do it even more. The E-4 Mafia will straight up disappear when needed, entire supply chains will stop cold. Separation and disciplinary paperwork will just not get sent.
Or France, which I remind you has thermonuclear weapons, will start selling said thermonuclear weapons to the rest of the EU, which then enables them to conduct retaliatory strategic strikes on Russia if it invades. Iran immediately develops and deploys thermonuclear weapons (they really only need to put the things together, they have all the parts they need) for strategic or tactical strikes against Israel. Japan, South Korea, Taiwan and Australia will acquire thermonuclear weapons for self-defense once the US nuclear umbrella is removed - and they have more than enough resources and know-how to just manufacture nuclear weapons from existing materials. India, with a higher population than China and an existing strategic thermonuclear arsenal, can and will turn the entirety of the Indian Ocean into a no-passage zone simply by attacking merchant transit lanes with their destroyers, effectively blockading China from much-needed Middle Eastern fuel and African minerals.
And if Putin decides to use tactical nuclear weapons in Ukraine or Europe? Pandora’s box is open, baby. Nukes deployed all over the world, mushroom clouds galore. You get cancer, and YOU get cancer, and YOU get cancer, everybody gets cancer.