I have seen this on a grand scale - 72MM LOC over multiple versions (10 year span) of multiple products by the same well-known software company. The occurrence

I have seen this on a grand scale - 72MM LOC over multiple versions (10 year span) of multiple products by the same well-known software company. The occurrence of nearly identical code was the most surprising find. One product had minimal redundancy. It used a plug-in architecture for the entire application - not just for extensions.