Yes. Definitely, sustained poor management can lead to a company's downfall. You have to continually sabotage your company to kill it. Just mediocre management or incoherent management won't do it. (But it might set the stage for worse decisions)

Google does seem to sabotage a lot of its products, but so far hasn't really sabotaged its core products or its company. As long as they don't destroy the dollar printing press (Adwords/search), they can keep pissing away money on dumb things and it won't kill them.