All American money so far was wasted on obsolete technology and strategy in Ukraine

"The United States and its allies spent billions to send tanks and other armored vehicles to Ukraine and to train newly formed units on advanced military tactics. But despite Ukraine's push through the summer and into the fall, Russian forces have largely held well.

For three months, U.S. and allied military personnel trained the nine brigades, 36,000 Ukrainian troops, in the basics of maneuver conflict. The theory, advanced by American strategists, was that only a heavy force could punch through hardened Russian lines and take Ukraine's southeastern coastline.

But while the United States taught Ukraine how to use the weaponry, the Russians dug in and prepared for the coming fight.

U.S. and Ukrainian strategists did not initially realize how much more Russians were strengthening their defenses. Ukrainian troops training in Germany practiced breaking through defenses far less strong than what they would eventually face.

The deep Russian defenses included more formidable minefields than seen anytime since the Korean Conflict, an old technology that slowed and then stopped the advancing Ukrainian Army. 

But it was also Russia's use of a variety of drones, including Chinese-made commercial drones, that fundamentally changed the nature of mechanized maneuver conflict.

In the past, breakthroughs along the front line could be exploited, allowing advancing forces to gain an advantage before their enemy could respond. Now, with the battlefield under observation almost constantly, it is difficult for either side to capitalize without being detected and stopped with either artillery or a counterattack.

Russian drones were able to cut communications between frontline troops and Ukraine's command post. Other drones were used to spot Ukraine's mine-sweeping teams, allowing Russia to send attack helicopters to strike them." [1]

1.   After Failed Counteroffensive, Ukraine and U.S. Begin Again: [Foreign Desk]. Barnes, Julian E; Schmitt, Eric; Sanger, David E; Gibbons-Neff, Thomas.  New York Times, Late Edition (East Coast); New York, N.Y.. 13 Dec 2023: A.4.