What's a better way to conduct street fundraising for organizations that need money?

I see people street-fundraising for various non-profits all the time in my city, but my impression is that most everyone says “no,” or “sorry, don’t have time.” For those that do stop and listen to the elevator speech, most seem to say “no” when they realize they are being asked to contribute on a monthly basis.

Do the funds they raise exceed the cost of their efforts? If not, what’s a better way to do it?