"The sanctions have already had a profound impact on the market valuations of Russian companies"
And all that means is that somebody else can pick up the physical capital for next to nothing. Which is what the nationalisation process Putin announced allows. Essentially if the West pulls out, then the Russians will confiscate everything physical and carry on producing in the same way. All that is lost is the monetary value extraction to the West, which is then diverted to the Russian Treasury.
"Their ability to conduct a military campaign is going to be severely limited by the lack of available inputs and capital as well, in a mechanical way."
How is it? What are the Russians, Russia being a country that can put people on the International Space Station, lacking in physical terms? They always have as much money as they require because they have their own currency and it has a floating exchange rate which means that it always circulates within the Russian currency area no matter what.
That means Russia can provide whatever liquidity is required to allow internal production to continue, and the Russian tax system - which requires payment in rubles - can be relied upon to drive the system.
Russia doesn't need up to date Western equipment. Guns and bullets made 1980s style will still kill people very effectively.
So they have all the available physical inputs, and all the necessary physical capital. Monetary capital is never an issue in a nation with its own currency. Plus if the West doesn't want Russia's exports, they can move people from that industry to the War Machine.
The only people that lose there is the West. Less natural resources in circulation, higher prices, less output. China, on the other hand, gets an energy discount which will be reflected in the cost of Chinese output.
I doubt very much that sanctions will impede the Russians. What it may do is get the West to re-evaluate what they believe. In particular whether 'the mighty dollar' really is that mighty after all.
What people seem to forget is that the value of the ruble in US dollars is utterly irrelevant to Russians in Russia. The price of their bread in rubles is unlike to change because of it, nor is the availability of that bread.
If we want to stop Russia, we have to put boots on the ground. I'm not sure the West is ready to face up to that uncomfortable truth.