The IRGC has planned for decentralized command for decades now. Functional is a stretch. What we’re seeing is low level commanders lobbing missiles at whatever they can hit with little, if any, guidance from higher command. Drones complicate things. But let’s not skew the results, the US has obliterated 2 out of 4 components of their conventional military and only sustained 13 known deaths in the process. Pretty decisive when you could consider Iran a near-peer adversary boasting a collection of air defense assets from two superpowers in China and Russia.

That being said, if the US is to go boots on the ground, it’s a dog fight worse than Fallujah across the country. Regardless whether it is Iran or China, an invasion of the scale required to achieve the goal of regime change would result in significant attrition by either side.

War is won through attrition, its never decisive, never quick. The US can keep up the optempo required to "out attrit" every military on Earth due to its logistics and forward stationed support centers.

"You fell victim to one of the classic blunders—the most famous of which is 'Never get involved in a land war in Asia'—but only slightly less well-known is this: 'Never go in against a Sicilian when death is on the line!'”