For a while I was employed at a shop that was a sort of unified platform and on that platform we would support a number of tools - these tools were usually developed by contractors that would get a complex set of business rules and build a solution to fit - then we FTEs would take care of the plumbing and platform tech debt... Unlike how a lot of places like that might look with outsourcing our contractor pool was pretty steady so while they didn't technically continuously work for the company they were essentially co-workers.
It was an interesting place to be but suffered greatly from a lack of permanence in the roster - for a few years tings were great - then some of our regulars moved on and were replaced with more flaky people. I assume it was just the specific mix of folks that made that setup sustainable while it was.
Care to elaborate on that more? Curious to hear what kind of work streams you were a part of, and how they differ from the more 'collaborative' norm of today.