They employ you and take all the risk away. If the idea fails, you move to a new one. If it succeeds, you get a large cut of equity.

Think about it more as an alternative to working at FAANG as it sits closer to salaried employment, but with much more tangible benefits should you succeed.

Rather than shotgun every idea that walks in the front door, studios deeply think about what will work and set off to build those ideas and staff them with good teams relevant to the problem domain.

They don’t really take the risk away. The startup can easily fail, leading to having to find new employment, probably the founder was making less than in a corporate job. Also there’s the risk of being replaced if you do succeed

This. I've seen multiple sad stories around of me of studio-incepted ventures, whose founders were replaced once the company started to be successful and the higher hand decided that they were no longer needed; obviously this part of the journey is not advertised on the brochure.