In theory, that's how it works in practice. In practice, though, the shareholders have a lot less power than that: they only get to vote at the AGM, and that's very much a managed democracy - the managers being the C-suite, and the majority of shares held by institutional investors who will vote whatever way is recommended by the officers.

I don't think it's even true in theory since corporations live in a larger context of the country or countries they are in.

As for countries themselves, we could argue that they also live in a context of all the other countries, but I would say that for the reasonably large ones it is the case their political will is roughly equivalent to the collective sum.