There are multiple types of value. Some of which that you often see in startups is calculable. For instance if the strike price is X and the last funding was at Y then there's an intrinsic value to the options of Y-X. If that's positive you can make an estimate of the likelihood of the company being viable long enough to realize that value and then discount that value by that amount.

EVERYTHING involves risk. A risk adjusted calculation isn't a guarantee but it's also not irrelevant simply because there's risk.

If I will pay you $1 for every number that comes up on the dice, unless its a 1 in which case I pay you nothing, would you ante up $0.50? You seem to be arguing that because there's a chance a 1 could come up, that a ticket for that game isn't worth $0.50.

"Estimate", "likelihood", "viable long enough", "realize that value", "risk", "adjusted calculation", "isn't a guarantee". These words and phrases do not inspire confidence.

Also, your analogy if full of it. You make it sound like options will pay out 5/6ths of the time. Adjust your analogy to rolling a 100,000-sided die with a couple of numbers that pay out, and we might be closer to the reality. With those adjusted numbers, no you cannot have my $0.50.

You can take the outside view on the company. There are N companies in a comparable situation, and of those companies M of them failed. M/N is approximately what you should believe the failure risk to be.