Well, version control wasn't always a thing and people got by just the same. So I can see how it could be done but the key is 'effectively' and the ability to quickly review and accord changes to a larger code base as well as to compare versions in a divide-and-conquer manner to see where a particular issue got introduced is priceless. So it would be a bit like trying to drive with the handbrake on, you can do it but it isn't an advantage.
Having Googled it, CVS came out in 1990, and there wer other pre cursor systems. So, pre-widespread internet and collaboration, yes, maybe people had some limited control systems that worked, but I don't think it even comes close.
CVS came out in 1986, and it is built on top of RCS, which dates to 1983.[0]
RCS was an alternative to SCCS, which was written for the IBM System/370 in 1972.[1][2]
All of these are very workable for software development by a co-located group of engineers. They are full-featured, not "limited". CVS is currently used by OpenBSD.[3]
And the car was invented in the early late 1800's and yet there are people who use bicycles.
The date when something is invented or comes into common usage does not automatically imply that everybody should use them. Though in the case of version control there are no good reasons not to use it that I'm aware of, even so, some people don't seem to require it to be able to be both productive and qualitatively at a very high level.
