Well, of course it doesn't necessarily follow. The fact that a resource-limited agent's estimates sometimes prove inaccurate doesn't imply that their estimates are not probabilities. E.g. see here:

Probability is a measure of the expectation that an event will occur or a statement is true. Probabilities are given a value between 0 (will not occur) and 1 (will occur). The higher the probability of an event, the more certain we are that the event will occur.