Sometimes they can be well architected to a fault! I worked on a periphery of a big mainframe system that was designed and implemented before I was born. I thi

Sometimes they can be well architected to a fault! I worked on a periphery of a big mainframe system that was designed and implemented before I was born. I think release 1 was in 1975. It still runs really well and is hard to displace because operationally, even though the people who understood it fully are retired or dead, they left behind strong materials so a moderately intelligent person can run everything. The “other” systems, old .Net, Java, etc that support the interfaces to the old app are hot garbage, and tend to steal the budget dollars that are needed to migrate off the 1970s stuff. My team had to fix one of these… argh.