"Stock photography" covers a lot of ground. I don't see company art directors shifting to generative AI--at least not yet--for a variety of reasons, including legal concerns. However, you'll probably see a lot of use for people looking for graphics, any graphics to illustrate things. But for content like that, people today are probably mostly using Creative Commons or (more commonly) just grabbing stuff of the Internet.

That's a statement about 2023. I don't pretend to know what will be the case in five years.