That's some really stupid circular logic.
Of course either side getting more tanks will enhance their capability for maneuver warfare, which is what this conflict is largely driven on. Both sides have used combined armor and infantry to good effect. The Ukrainians more so. The reason tanks are just driving forward as fast as they can manage is because the Russians have mined the fuck out of their front. Ukraine knows this. Hell, everyone knows this. Why in gods name would they Zerg rush across open terrain into minefields with pre-bracketed artillery? The success has been to push forward slowly, until you can push the front back a bit, but more importantly, to hit new logistical targets and supply routes.
That's what the Russians can't stop. They can slow it down by playing the balls-out defense they've been forced to resort to. If Ukraine can keep that up, they will retake all they want. The last thing they need to do is start trying to run the gauntlet 20+ miles behind a front and losing 80% of the attacking army to achieve what they otherwise could in more time but with much less casualties.
You managed to take a really common sense tactic and turn it, somehow, into proof that russia has thwarted US/NATO tanks. And if the opposite scenario played out, and Ukraine just threw away assets in a stupid push, that would also be proof that russia thwarted US/NATO tanks. So whatever happens, russia looks good here.
Pure idiocy.