It may have already been said in this thread, but those tanks, and other advanced weaponry, are really critical at this juncture. ISW recently noted that Putin may plan to put Russia on a long-term war footing, redirecting its economy to building up its (relatively) decrepit military. Thus if this drags out, Ukraine may face a more formidable Russian military in a few years. Consequently, Ukraine has a limited amount of time to move Russian forces off its land. Otherwise it, and the West, may face a years-long war of attrition:
"Russian Defense Minister Sergey Shoigu announced on January 17 that he will implement Russian President Vladimir Putin's directive to conduct large-scale military reforms between 2023-2026 to expand Russia's conventional armed forces, likely in preparation for a protracted war in Ukraine and also to set conditions to build a significantly stronger Russian military quickly....Russia’s ability to generate large-scale rapid change in its military capacity depends on President Vladimir Putin’s willingness to redirect large portions of the federal budget to a military buildup and putting Russia on something like a war footing for several years. There are signs that Putin might be willing to do so. Reform and expansion on the scale Shoigu outlined will not happen in time to affect the war in Ukraine materially for many months, but it could change the correlation of forces going into 2024, and it could establish conditions for a much more formidable Russian military threat to its neighbors, including NATO, in the coming years. Ukraine likely continues to have a window of opportunity into and through the summer if the West provides it the support it needs"
This page collects ISW and CTP's updates on the conflict in Ukraine. In late February 2022, ISW began publishing daily synthetic products covering key events related to renewed Russian aggression against Ukraine.
www.understandingwar.org