Sorry, but I disagree with your logic and think your explanation borders between nonsensical and flat out ridiculous. If Ukraine was indeed winning this war and Russia was teetering on the brink of defeat, there would be absolutely no reason to provide them with top of line main battle tanks from NATO.
Regardless of either of our opinions, neither of us knows for sure who is winning but we will eventually find out when the war ends.
Until then, everything is propaganda.
Your thinking is bassackwards, you don’t shut down logistics at any time during a war, and you have to feed the machine constantly until the surrender papers are signed.
When your forces are gaining on the battlefield you do not cut off their support.
The West was hesitant to send expensive gear to Ukraine at first because it was thought Russia would roll over them in days, which dragged out to months until eventually, the West decided that Ukraine was worth the greater investment in war goods.