It’s still a thing in big corps. We have all business nanoservices (I can’t call them micro) at JVM (moving to Kotlin from Java) and any try using Go is silently killed by those JVM talibans.
I wonder if no one really thought there about rewrite that will still connect with all old dependencies with old protocols, but also will expose new kind of API that can be used by next rewritten block.
We also had mainframe, we used Oracle. It turned out that casual server is also reliable in long term and we restarted them only for upgrades of OS. Of course moving to some distributed, fault tolerant option also feels like good direction, but instead not-doing the perfect rewrite at once you can do it two/three step migration. Costs nowadays? You already fixed that.