Other businesses.
If the "people don't have jobs" due to AI, consumer goods companies will go out of business, and society's resources will get redirected to non-consumer businesses and the passion projects of the ownership class.
Outside Soviet Russia, there has to be an end consumer in there somewhere. There isn't such a thing as a truly "non-consumer business."
And I answered that. The ultimate consumers will be a group of wealthy people who control the productive resources using AI and use them to pursue their personal goals. There will be some B2B exchanges between those people, and perhaps a smallish cadre of employees who's labor is still useful to the wealthy, but most commerce as we know it will grind to a halt because the vast majority workers' labor won't be valuable to those who could pay them.
I think this is a dead angle for a lot of AI experts. That sudden bump in efficiency might ruin large parts of the markets businesseses are built upon.