Software doesn't need to be readable anymore. it needs to be explainable

It doesn't need to be readable, until it does.

But of course anyone is free to hand their business to another company on a silver platter and to make themselves entirely dependent on AI providers.

(Not everyone is a huge company. There are many, many, many small and medium companies out there. And many of them WILL die, if the prices increase and they can't handle their codebases anymore.)

Readability is the source of the explain part. Eventually one needs all the details and that means source code. Anything else is a biased summary which is inaccurate because small or big important will be left out.