I think you may be right for jobs you _are_ underqualified for, but what about all the jobs you only _think_ you're underqualified for? You really have no way

I think you may be right for jobs you _are_ underqualified for, but what about all the jobs you only _think_ you're underqualified for? You really have no way of knowing if you're underqualified or not from the amount of information about any particular job you might come across (on a job board or a company's website). Now obviously they may list a bunch of technologies you've never worked for, but even then they might be willing to let a smart person learn.