Doesn't mean their methods need to be cartoony/bond villian though. Burke is a good example of greed done right, his first plan was try and be subtle, investigate first and then try and get exclusive rights. When that went wrong and his actions exposed, he then panicked and planned to infect Ripley and Newt, which was clearly desperation, and you can see the nervousness and sweat while it was happening.
Point being, as scummy as Burke was, he was not mustache twirling evil.