"... and then the sky opened up and God came down, shouting: 'Well then, buy yourself a damn lotto ticket!'"
This is the punchline to a joke about how praying (manifesting), wishing, and lighting candles is not enough. You need to do your part for whatever it is you want, even for winning the lottery. Though while someone is manifesting or lighting candles, chances are that the inspiration is going to hit them to do whatever is necessary. So indirectly the practice of manifesting does work.
That's a nice way of looking at it - it can halp but it ain't on its own enough!