I think you might have answered your own question, the operative concept being “Structure.” Start-ups do not have this by the vary nature of what they are. I think for one to think about working for a start-up, they have to enjoy unstructured environments. Ultimately what you learn is how to create processes, systems, products at scale. Conversely a large company, like a Goldman Sachs is a great training ground before you venture into the start-up world b/c you can now have a skillset to add (so you are a structure enabling element). Thanks for asking.