It's a lot, but not nearly enough to break Russian capabilities. If it's one thing they know how to do, it's throwing materiel and warm bodies at a conflict till the opponent is overwhelmed. In the battle of Kursk in WW2, the sovjets lost upwards of 6000 tanks and 800000 soldiers (of which 250000 were KIA) in the span of six weeks.
Russia will not be defeated militarily, but with western support Ukraine can hold on long enough to make Putin's political situation so unstable that pulling out is the best option, or he gets coup'd. And Ukraine is holding on well, for now. Slava Ukraini!
I wouldn't think they actually can afford to lose that many tanks in this day and age. A T72 or T90 is infinitely more complex than a T34, and Russia is already showing signs of exhaustion.
After Finland joined NATO, they actually drew down their forces there, meaning they themselves don't think fighting NATO is on the table. Also, most of their AA bases across the globe have been emptied out months ago, while Ukraine is just putting the pressure on with its new F16s.
Empires fall gradually, then suddenly. Not many people predicted the fall of the USSR either.
If it's one thing they know how to do, it's throwing materiel and warm bodies at a conflict till the opponent is overwhelmed.
There's a massive difference between the Soviet union in 1940 and Russia today. For example:
Warm bodies are a lot more scarce than they used to be. In the 1930s, the Soviet economy was massively more forgiving than today. A LOT of them were basically little better than subsistence farmers, and agriculture was rapidly industrializing. This made for an amazing opportunity to extract a LOT of manpower from the population. And much of that force was "frontoviki", which is basically the lightest of light infantry, a guy with a rifle, helmet and some spare ammo. That's not how you wins wars today. Today, Russia has a massively aging population, and many of the younger people who could get out, got out.
Material is a lot more scarce than it used to be. The Soviet Union included Ukraine, and that had a LOT of factories, which were moved to the east when Germany invaded them. But back in 1941, you could make a tank basically with a rivet gun and a couple of wrenches. They were building airplanes quite literally in farmers barns. None of that applies anymore, you need massively more technology, and throwing more people at it won't get you, for example, more jet engines, radar absorbent materials or advanced night vision sights.
The lend-lease is going to the other side this time. People hugely underestimate just what an insane amount of material came from the other allies. The majority of high octane fuel and almost all airplane fuel was American. Almost every locomotive running in 1945 was American. Every other bullet and bomb fired was American. Every third truck was American, and many of Soviet ones used american or British engines. Basically every radar and sonar set was British. They're still digging up British Hurricane fighters in Ukraine that the soviets buried rather than giving back. The allies sent Russia almost half a kilo of food per Soviet soldier per day.
That WWII fight was the combined strength of the USSR, motivated to defend itself from invasion, supported with major lend-lease backing from the US.
Today is totally different. It's a single, demographically-fucked country, alone, in a barbaric war of conquest. Russia can absolutely be defeated militarily.
I agree that Russia will not likely be defeated militarily (in the sense of 'fought to the point of literal material exhaustion'), but the Sovs were a very different beast than the modern Russian federation. Modern Russia doesn't have that capacity to spend - in manpower or in organization. If modern Russia had quarter of a million troops KIA in six weeks, not only would it utterly wreck their entire war effort, it would very likely sink the very future of their country.
I mean, they're doing a bang-up job of that as it is, but you know what I mean.
Ukraine reports almost 9000 tanks destroyed. Some time ago I made a rough calculation on what wikipedia lists on Russian military hardware and based on that they had around 14 000 tanks before the war started. I don't think that even Russians themselves know how many of those are in any kind of usable and/or repairable state and which are just scrap metal laying on some field in the middle of nowehere stripped of anything useful.
Additionally, Ukraine reported destroyed tanks in single digits per day for quite a while, but for last few days the numbers have gone up, I'd guess because of counter attacks in Kursk and/or because Ukraine is finally receiving some ammunition for their hardware. Whatever the case might be, majority of Russian tanks are destroyed anyways and I'd guess that what's left is soviet relics and a significant portion of those are just scrap metal (which is of course a useful resource) instead of anything even close to combat ready.
I hope not - that means the war goes on for a long time - Russia is only producing about 3 tanks a day (most of them restored tanks from Soviet storage). I hope Ukraine can win faster than that.