It depends on how traumatic your founder's experience actually was. Having a boss again can be quite relieving in the beginning. The nightmare is over. But then... well, if you are a true entrepreneur, sooner or later you are going to have ideas again and you become restless. You managed to get over founders PTSD, you want to learn from your past failures and do it again. And if entrepreneurship is part of your character, you can't fight it, it's going to happen. I did it three times. The third time was the charm.