We had colleagues, photocopiers and telephones. A good lab had a large library and many shelf-feet of schematics. Search was difficult, sure, but copy pasta was just as fundamental to a young engineer then as it is now. The consequences for bad judgement were however a bit smokier (is that why my memories are hazy?)

The “trust what worked and copy” mentality and potentially lack of access to the original designer sometimes can lead young engineers read too much into the intent of designs and be unwilling to consider changes. Sometimes this helps keep the “magic smoke” in, and sometimes the original designs truly are elegant, but other times it can be an impediment to progress. “But this is the founders’ work! How could we possibly improve on that!” I’ve been in some design reviews like that. Old designs sometimes become legendary and thus hard to convince others to change, even when needed.