If I'm reading you correctly you are arguing to something slightly different than what OP said. OP says that if a company can't go cash flow positive it is worthless, you say there there is always a chance that a company might experience a sudden turn around and go cash flow positive. Both are true.

However, theory and practice are identical only in theory. If there is a company with negative projected cash flows relying on a negative-expected-value project succeeding unexpectedly that company is probably near worthless. If ordinary investors are relying on "maybe things won't turn out the way we expect them to"-style logic to make their investment decisions then the market is doomed.