Well, Google doesn't want anyone to spend on SEO. They just want people to make sites that their spiders understand. You can have a site that gets indexed and ranked without spending on PPC. PPC is a lot faster and throws off more data more quickly that SEO. But no, Google doesn't directly or indirectly force spending on ads. There is no evidence that you get better organic positioning through PPC spending. Not spending on search as a channel would be silly, though.