The U.S. government and its media allies have a deep distrust factor in the half of the population that voted for Trump. Spreading nonsensical stories about the Russian Army running short on supplies and about to fail in two weeks is confirmation bias for that distrust. The Russian military may be meeting with more resistance than they anticipated, and the Ukrainians may be replicating what the Finns did to the Soviets in 1939. However, it is difficult to believe the MSM narrative when they have lied on so many matters in the recent past.
The propaganda game is this:
—Russia advances on cities which means civilian deaths.
That is proof that Russia is evil and desperate.
—Russia does not advance on cities.
That means they have run out of supplies and are stuck in the mud. The mission is a failure.
Propaganda does not care if it is self-contradictory.
The stupid dupes that believe it are unable to figure out the contradiction.