I don't quite follow how charging money eliminates "…unqualified, and other candidates who really don't stand a chance" from the selection pool.
What does charging a fee have to do with qualification, and what other factor makes them not stand a chance (and which is also mitigated by charging a fee)?
Sure, which accounts for the "not serious" candidates but does not, IMO, explain the claim that it will filter "unqualified" candidates or those who "don't stand a chance."
They will self-select out because it will not be worth the marginal cost. If the marginal cost is 0, then it is worth the effort for the perceived long-shot chance. You are right in that this will not eliminate the truly deluded.
What does charging a fee have to do with qualification, and what other factor makes them not stand a chance (and which is also mitigated by charging a fee)?