And 30 years later? At some point it is necessary to rethink how a technology works. There are reasons why the world eventually gave up on freon and moved on to chemicals that were safer. There is a reason why telephone systems eventually went digital, even though the old systems worked.
In terms of software, a perfect example is Microsoft.
I'm not saying it's unwise to upgrade technology, but things tend to stick around for a long time. Because it works.
The amount of time and resources it takes for the skill gap to close when you're talking about a core techongoly that almost any IT person is knowledgeable in. It's insane. We're talking generations.
It's going to take a long time for that to change.