As many experienced commenters below have already noted, nearly any piece of substantial, revenue-generating, long-lived code will ascend to a place full of dragons and mysticism. The more interesting debates revolve around:
1) How did it get that way, and what can we learn from that?
2) Is it inevitable that all software will end up like that?
3) How can an organization ever successfully sunset or move to a more maintainable system? Or should they even aspire to that?
I don't know exactly what they should have done and when, but it seems like rewrites are going to be necessary, and it sure would be nice to start rewriting a system while you still have someone who can explain what it does.
In the post-Y2K years, I heard a lot about how the next order of business was going to be to replace all those systems in health care, banking, etc, especially as a generation went into retirement. But, here it is 2018 and there are still articles Food for thought.
1) How did it get that way, and what can we learn from that? 2) Is it inevitable that all software will end up like that? 3) How can an organization ever successfully sunset or move to a more maintainable system? Or should they even aspire to that?