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.

Idea's are worth a nickel. Execution is worth millions.

(I can't remember who originally said that, but Ive remembered it. Might have been Spolsky?)

But a company willing to change as they see the need is likely to have at least some success. A willingness to change is worth half a dozen ideas.