I doubt you’ll find many people who build their own sound systems anymore or even people who won’t just buy everything they need themselves, especially with active PA systems. You might find what you’re talking about in bands because most people will have their own hardware like instruments, pedals, amps, cabinets, etc.
Now on the other hand I do know a group who collaborates on their DJing, three DJs total and among them they contribute a van, a PA system, a lighting truss system, various disco lighting, and a hazer. Between them all they can put on a much bigger show than any one of them alone.