The US can't admit that they failed to prepare Ukraine sufficiently these past 8 years or accurately predict Russian actions, or that Ukraine ground force will die in the Donbass. They already committed to a certain 'outcome', the Pentagon's message is tailored to it as well as the MIC funded US " think tanks" like the neocon/corrupt ISW.
I suspect that Putin/Russian leadership are playing evil 4-D chess, if he destroys the Ukrainian armed forces he would have destroyed the 2nd biggest army in Europe with a 200K man army. Unprecedented in military history.
Russian military deception - Wikipedia
Ukrainian military deaths are now definitely in the tens of thousands, and according to Ukraine's defense minister, probably under 100,000 dead.
If minimum 200 Ukr are KIA/MIA per day for 156 days this would be 31,200 dead/mia and up to 218,400 casualties. Ukrainian deaths, according to their politicians, range from 600 killed a day to 30 killed a day.