[jamesmishra]

I don't like Oracle and I'm a big proponent of learning new things, but just to play Devil's Advocate:

The Oracle ecosystem is still enormous, with many lucrative enterprise customers that will never ever migrate away. Your friend might consider doubling down on her expertise and simply competing for better-paying Oracle gigs.

That said, I don't think it has to be an either/or. I think people can learn a new tech stack without abandoning an old one.