The Russian arms industry can produce 600 new tanks a year. This is really a huge number, underlining the industrial capabilities of Russia. However, it may also not be enough to keep the war in Ukraine going for many years to come.
Russia's military industry is working overtime to support the war
According to minusrus they've lost 7193 tanks out of 3300 Russia had before the war started. I sincerely hope that the article is correct, but so far they've been able to replace lost hardware with a decent rate with manufacturing and presumably purchasing from their allies.
One can hope that the current massive attack ends with the Swan Lake on Russian tv's, but right now I'm more worried if Ukraine can hold the lines long enough for that to happen. They really need reinforcements, it's pretty difficult to fight a war without ammunition.
Russia started with 14000 tank chassis. No one really can know to what extent any of those were still usable. Most of them probably weren't. The best analysis I've seen has been from Covert Cabal who attempts to track the number of chassis left in storage and their condition from satelite imagery. IIRC they also give Russia about 1-2 more years.
Wikipedia lists a total of 14000 tanks, reserves included, (majority being T-72 and modernized variants) + unknown number of T-54 and T-64. I suppose even the russians don't know how many of those are in combat ready shape by any stretch, but apparently at least a half (not counting ones they've bought from elsewhere).
So, as the war has been going for two years that 1-2 years more sounds plausible. If current news are anything to go by I'm quite afraid that Ukraine doesn't have that much unless they really start receiving reinforcements from Europe and US. And should Ukraine collapse it would take 5-10(ish) years for Russia to rebuild enough hardware to do the very same thing with some other country. Maybe not with a NATO country and maybe not one the global west is as interested as Ukraine, but it could (or would, depending on which prediction you want to follow) happen.
Plus the wild card of China, who no doubt are following the situation and spesifically western response pretty closely. I wonder what happened to those 800 000 artillery shells Czechs promised to gather...
One out of two gets a rifle. The one with the rifle shoots, the one without follows him. When the one with the rifle gets killed, the one who is following picks up the rifle and shoots