Ideas aren't worth nothing. Most startups suffer from being bad ideas - and not in the "so-bad-it's-good" way that pg talked about. They're slightly tweaked copies of another idea, or something where there just isn't any money.
Every startup starts off as a bad idea. That's kinda the point of the lean process: you've got to start somewhere but you have no idea what your customers actually want. So you do a whole bunch of experiments to find out what they do want.
Doing the experiments takes engineers and money, which are important. The idea you start with is not. This is why investors invest in teams not ideas.