anyway whenever i hear about stuff like this and the millennium challenge and how long its been since america fought a conventional war where this sort of shit could be tested against real opponents, it always reminds me of this

We did conventional war back in the 90s during Desert Storm, and we basically mopped the floor with the Iraqi Army - then the 5th largest in the world. But yes, a lot of those battles really did boil down to "My tank can shoot twice as far and drive twice as fast as your tank and can actually hit what its aiming at" conflicts, wherein a dozen American vehicles just backpeddled and decimated an Iraqi tank battalion.

The modern US military still does periodically have to deal with quasi-combat situations, particularly in air defense. But the theory is that our tech so vastly outstrips the competition that there really isn't a countermeasure you can deploy against it. The Millennial Challenge was a shock, because Americans assumed you could just roll through the Iranian military unimpeded. But the real "defeat" in that scenario was in expected American casualties (which officers predicted would be near-zero, but opposition commanders proved would be far higher). America still "won" the conflict with overwhelming force.

These scenarios definitely illustrate how American military units are under-trained and unprepared for a full-scale conflict. But anyone who thinks the US couldn't wipe the UK off the map in a serious conflict is crazy. There's a huge gulf between believing the US units are invincible and inexhaustible, and that they can't do horrific damage in a stand-up battle.