It helps too that the local level has much less attention, less stakes, and is much less of an echo chamber. Google's (probably) not going to offer to fund your next city council campaign war chest for allowing them to put a bridge in, but they might fund a senator who could help them crush their competitors on a national, or international, scale. It also helps that at the national level, its often not "me vs you" specifically, but rather amorphous lobbying groups that theoretically represent an industry's wishes. "Don't you want to help promote strong, beneficial laws for competitive American businesses?" vs "Want to do me a favor?"