Locations are unique. Anything that is site specific has to be custom. So long as you're in the business of delivering site specific artifacts, then the business is closer to the free-lance end of the spectrum.
Products are products because they are generic/universal and can scale. Museums don't buy products. Maybe there's a middle point of a platform that the end user can customize. On the other hand, museums and events like to hire consultants to blame when things go wrong.
There are businesses that don't scale because completion of one piece of work product only has a correlation to future
production of work products. I mean a successful installation contract increases the odds of getting another installation contract but has no meaningful effect on the effort to complete the second contract.
Good luck.