The nature of private property and free markets, along with basic reason move people to mitigate risk. As I said, the most critical aspect of this kind of asset is cash flow, not the underlying value of the asset itself.
For example you purchase RE for $1 million. It cash flows positively to the tune of $6000/month after Principal, Interest, Taxes, Insurance (PITI). Due to some government regulation you are forced to value the property at $0. What happened?
From the banks perspective nothing as long as you conform to your loan terms. They don't do interim appraisals until it is time to refinance the property. These flows are easily valued and have been for a long time. It is not a confusing process.
The Marxist part of your analogy is this statement: Let’s say a bank buys a bunch of lottery tickets.
No business person gambles. Marxists present the free market as a gamble. All life is full of risks and the best way to mitigate risk is through the free enterprise system. The alternative, which Marxists want and prefer, is government intervention, hence government control, hence our current financial crisis.
More of the same.
BTW here's a quote for you: Gambling is a tax on ignorance - Warren Buffet
Sigh...don't get hung up on semantics...One person's risk is another's gamble. The point is that business people don't have perfect knowledge of the future and have to make investments understanding that they won't necessarily turn out the way they'd hope.