The owner of any public limited company is a shareholder. Even many smaller ones have a shareholder even if the person managing it is the main shareholder themselves.
The shareholders in the majority of any decent size are not the senior business managers however.*
* the job title is irrelevant, manager/CEO/CFO/director etc. Those dictating the business strategy is who I am referring to.
Typically when the managers (CEO and downwards) do things that are not in the best interests of the owners you see some kind of friction develop and it can result in the shareholders removing the CEO and/or others.
Its the managers job to do the best thing for the business owners. Literally.
What the managers do (or should do) is balance the best short and long term benefits. IE if there is the opportunity to take excessive profits they need to balance if that will end up as a negative later, encourage further entrants to the market, attract legislation etc
No logical person would attempt to lower corporation tax by reducing profit. Tax % would have to be (marginally) over 100% for that to ever make sense.