Speaking as someone who has juggled both a full-time job and a part-time startup on the side before, I can answer this: both of them contributed immensely to my professional development, but in different ways, since the business domains were very different (which also meant developing proficiencies with different technologies and tooling).
My perspective is different - not disagreeing with yours.
My goal is to constantly be “putting myself out of a job”. That means I need to be able to recognize a problem or opportunity, understand the business context, do enough of an MVP or POC that the rest of the organization understands, train and move on.
Sometimes the internal organization doesn’t have the desire or capacity to maintain or evolve the solution. In that case it’s my job to find an outside consulting company.
