I would be surprised if programmers couldn't generally quickly pick up a new domain. I presume we're not talking 5,000 people doing heavy research (wouldn't that be O-1 anyway?), and I don't see how product development work becomes more complicated when you call it AI. e.g. you don't need a PhD to hook calls to a model into VS Code or to build the API and infrastructure around calling the model or data pipelines or all the other 90% of actually making it useful.

I wouldn't call developers fungible, but certainly good developers are adaptable.

I don't think Microsoft is lacking a supply of people capable of doing things, they're lacking a culture that lets you do things. The most annoying thing about Microsoft culture is that you have to pretend that Satya Nadella fixed it.