The "playpen" or "sandbox" itself doesn't have to be "wildly" successful, but the entrepreneur must have the wherewithal to launch a company with a sufficiently large team to execute all those ideas. This entails either a successful exit for a prior business or pre-existing resources. It is possible to do so without such resources, but that would mean a much smaller vision and more limited sandbox.

It is interesting that for the entrepreneur the business becomes play. Meanwhile, for the employees, it is often still work. I wonder how this affects the work-life balance. Since it is the entrepreneur's passion and vision, he or she may very well not desire the same balance the team needs.