Now something goes wrong. A customer isn't getting what they ordered. What do you do about it?
Do you just drop the customer? Well that's lost revenue, or an easy win for another company, you don't want to do that. Maybe you tell the AI to fix the customer in a particular way and hope it will do so. If it does, all it takes is having a human available to fix it (a customer support dept, even if tier 2), but if it doesn't fix it now you still need all the software you needed before to fix it.
I've built line-of-business software before, and I've over-automated things before. Being able to inspect the state of systems, and being able to manually change things in software, is incredibly valuable. This is why spreadsheets run businesses.
My bet is that companies will still mostly buy the software they were buying before, but that some of the interactions with that software that humans would have done before, AI tools will action instead. All the same CMSs, CRMs, ERPs, and other TLAs will exist, they'll just be augmented with AI. They'll probably do some more interesting things with that AI, but they'll still exist in fundamentally the same way. Companies are not going to entrust their business to a black box that sometimes says no.