Russia's biggest source of income is their export of gas and oil. These are not sanctioned, the West is buying as much as ever and the profits are flowing straight into Putin's war chest.
> 2. He incorrectly assumed that Ukraine would fold in less than a week.
How do you know this? Russia has fought wars before, e.g. in Chechnya. They eventually won after bombing the whole country to ruins, but it took several years.
They sort of ended up sanctioned. You're right, there's nothing official, but no unconstrained buyer wants to touch energy exports from Russia.
Russia is struggling to sell its oil to unconstrained buyers [1]. Sure, Europe, in winter, with no ready alternative, is still buying, but that's about it it seems.
Also, while it's true global oil prices are sky-high, the rise in Russian oil is far more muted. Basically, there are many kinds of oil sold around the world (Brent, WTI, and many more). They usually move largely in lock step, as to a reasonable extent you can substitute one for another. But recently Urals is sold at a massive discount - because no one wants to touch it.
> How do you know this?
There are plenty of soft indications. Troops only given rations for 72-odd hours. Attempts at airborne strikes that are very rapid, but doomed to fail terribly with any but minimal resistance. Reports of Russia looking to "source" new troops - from Russian reserves, and Syrian, hmm, volunteers? All suggests the current length of the war exceeds plan A and plan B.
Of course Russia might still win a long, hard slog of a war, by bombing everything that moves...
[1] https://www.reuters.com/business/energy/us-has-not-sanctione... [2] https://www.neste.com/investors/market-data/urals-brent-pric...
Getting paid dollars for oil and gas doesn't do you much good when you can't spend those dollars on anything. Imports into Russia have stopped over the past week.
> How do you know this?
The propaganda leading up to the 'Minor peacekeeping action in the Donbass' certainly didn't sound like he was getting everyone ready for a forever-war.
> e.g. in Chechnya
To most Russians - even the warhawks, the war in Chechnya (much like the Winter War of 1939) was seen as a debacle and an utter embarrassment.
I mean, it's entirely possible that the war will end this week, and my second point is moot. But it's looking like it's quite possible that it won't.
1. He incorrectly assumed that he'd only be facing minor sanctions for starting a war of aggression. Given how many other countries have waged wars of aggression in the past few decades, this wasn't an insane assumption... given the information he had at the time.
2. He incorrectly assumed that Ukraine would fold in less than a week. Given how the first day of the invasion looked like the Russian army was driving westwards until there wasn't any gas in the tank, this wasn't an insane assumption... given the information he had at the time.
3. There is no 3, those were the two major contributors to the shit sandwich he's now serving to both Ukraine and Russia. All the crazy shit he says about eight-hundred year old history and nazis and so on and so forth isn't what he actually believes, it's intended for internal Russian media consumption.
So no, from the perspective of someone playing at empire-building, starting this war was only 'irrational' for him with the benefit of hind-sight.