I'm honestly stunned that people here are performatively math-illiterate.
Some companies experience liquidity events. Therefor the value of equity in those companies is positive. Some companies go out of business. Therefor the value of equity in those companies is zero.
If N is the ante hoc chance that a company will experience a liquidity event, then:
People aren’t saying the chance is literally zero. They are saying it is low enough that they can’t consider it reliable comp for income purposes in their own personal situations. I can’t say my experience has been any different so I don’t blame them. People commenting aren’t math illiterate. I’m kinda amazed you are taking things so literally when it’s so obvious to anybody reading how to interpret the discussion.
"Statistics" on its own doesn't tell you anything; you have to consider your own risk aversion. Only VCs can afford to be risk-neutral and only consider expected value.