People often ask assumptive questions that are based in bad information (why don't you do something that would pay you more money?). Not because they choose to be dumb; it's that they neglect to learn.
They don't know because they don't seek.
They don't seek because they assume, wrongly, that they know all they need to know.
This is why some percentage (depends who you ask as to what this percentage actually is) of college graduates never read another book in their lives: we think what we know is all there is to know. That, or we just don't wish to further our learning.
This doesn't mean these are bad people. On the contrary, they're good people who have made, as Jim Rohn said, errors in judgement.
What is failure? A string of errors in judgement compounded over time.
Base your beliefs in what you know, not in what you heard or what some uninformed person told you or what you wish to be accurate or what sounds good to your audience.
The results, just like the errors, accumulate slowly.