I think that’s silly and if policy is being made on the assumption that the Russian army would colapse in a week or two that’s pretty wreckless. Who knows with the bunch in power though (including milirary leadership). The US “struggled” with Afghanistan for 20 years and couldn’t overthrow the Syrian government. Syria, as a matter of fact, openly defied all red lines. I think the lesson to be learned by all of this is the one lesson that won’t be learned. All the military power in the world will not subdue a populus who is willing to fight back. A wiser people would consider moving all their expenditures to missle defense systems and stop burning money with offensive crap that can be fooled by some smoke and overcome by a few drones.
No one said a few weeks, and to your point unlike iraq, Afghanistan, Syria, Libya, Ukrainians are willing to do the fighting