Very nice analysis outside of the tAnk treads and sparkling objects that typically entertain the gamers on f.r.
You can only throw mass at the enemy for so long in modern warfare before the support system just collapses.
I think one additional problem that is being under-discussed is that the professional supply and logistics people that the Russians had in the active military when the war began likely have suffered significant casualties as well. That's especially true once HIMARs started hitting logistics/maintenance centers and command posts. So now they're bringing up new inexperienced troops, issuing them outdated equipments and supplies that may require a different supply chain, and you've probably lost a lot of your trained supply/maintenance people. That's just a recipe for disaster.
On the flip side, the Ukrainian military saved their country post-2014 by recognizing their weaknesses, and beginning the professionalization of their forces with NATO help.