With all due respect, that's an ignorant comment. Advertising, and especially television advertising, is absolutely, unquestionably influential. There is a huge and highly-profitable industry dedicated to delivering its influence, with countless business clients who pay billions of dollars for those well-proven results. If you don't recognize you're being influenced, it only reinforces just how effective it is.
You may be able to argue that Walker wasted his huge financial advantage by buying bad ads, and you could be right. His results strongly suggest otherwise, but I didn't see any of his ads personally so I can't offer first-hand judgment. Even if that was true, all it would show is Walker's campaign was inept, not that television ads aren't effective. When done correctly, they most certainly are. That is a fact.