Most electronics designs are more complicated than a single PCBA. Very often, designs are compartmentalized into multiple interconnected PCBAs, wiring harnesses, enclosures, mechanical fasteners, labels, packaging, and anything else necessary to run the design.
Revision control has made huge strides in the past 15 years. File repos no longer need dedicated IT employees to set up and maintain servers. Numerous providers offer turnkey solutions for revision control. The most popular and functional tool has been the git.