Actually in countries like Portugal or Germany, most clubs are owned by its members (or at the very least, 51% owned by its members), which can e.g. vote on its president.
You're not totally wrong about the 51% thing (although it's really 50% + 1 vote), but it's not like that is a panacea that keeps out corporate interests. Leverkusen and Wolfsberg are owned by Bayer and Volkswagen respectively (although I understand there's historical reasons for that) and Leipzig is 99% owned by Red Bull, but they only have 50% - 1 voting rights to comply.
