I don't think "laid back" is a good term to describe the most innovative workplaces. Here's why.
We've got good evidence that people need to be relaxed to be creative. If you ask people where they get good ideas they almost always describe a situation that's relaxed, with the body on autopilot and the mind free to roam. Examples are: talking a shower; driving: walking; washing dishes; exercising, etc.
Does that carry over to the workplace? Yes and no.
A relaxed and safe setting certainly makes it more likely that people will be creative, i.e. that they will come up with good ideas. But that's only part of the challenge.
For ideas to have an impact in business, they have to be modified, massaged and managed into something new. We call that process innovation.
For innovation to happen, people need to have good ideas, but they also have to be willing to share them and help turn them into productive changes. That happens in workplaces where people are engaged: competent and willing to pitch in.
A workplace with many engaged workers is often not "laid back." Workers are involved in doing productive things. They care about outcomes. That generates a lot of stress, even thought that stress is mostly positive.
For my money, the best workplace for creativity and innovation is one where workers feel safe and valued, but which has the high energy of a productive team.