There is not necessarily ONE corporate culture, but often several. There are sub-cultures, and there is nothing like an imposed culture or an emergent culture, it is a mix of both. There is a vision, which is usually brought in by the executive team, and which will give birth to some values, which will give birth to a culture. Then, what happens day-to-day will give birth to another culture. Then, there is history.
Also… I won’t mention any company to stay neutral, but I often met people who told me “there is a very strong culture in my company, here we do things like this.” Ok, why do we do things like this? “Because we always did.” And why did we always did? When scratching a bit, you realize you do things like this, but you don’t know why. Even though in the beginning, there might have been some thinker who said “we will do things like this, because it will work better.” When we lose the meaning of behaviors, we still behave the same because we love our company, we admire our company, so we have to fit the mould… we become very rigid and unable to change. The corporate culture, is it a good or a bad thing… It could be a good thing, when it serves a present vision, not one from the past, it could be a bad thing, when it is a legacy or when it relates to values imposed by communication which are not in line with what the company really is, or with how it works locally.