[candyman]

The maintenance budget the central administrative system at IBM in 1985 was $4B or (about $9.6B in current dollars.) The idea of moving something like this to the cloud is hard to comprehend. Even if it could be done it would take years and cost maybe $100B. And what would be the ROI versus building new applications or businesses. These are business critical systems built to run in a specific environment, it is very hard to justify moving them to another platform.

[DarkNova6]

Well, that is until the old system inevitably fails and has larger and larger outages. Critical knowledge is lost with each generation to keep it running.