Whilst it's interesting to imagine every company being run by the most aggressively rent seeking MBA-like AI, I don't think that will ever be the entire market.
I would guess it all comes down to risk. The future won't be uniform, it'll be poorly defused, just like then present.
People will make a value judgement on the types of corporations they want to deal with. The sort of company that no has employees will by necessity have to be very cheap compared to those that provide interactive human service.
Dealing with AI firms will be like dealing with an anonymous Chinese eBay seller. You'll effectively have no legal recourse as such and they won't discuss things but complaining might get you a replacement item or a full refund.
If it doesn't the product will have to be cheap enough to write off as a bad buy.
Let's hope cheap AI powered corps don't suck all the profit out of the market and we loose all firms capable of providing real services.
Or we end up paying for human service that's been quietly outsourced to AI much like we do for many big name manufactured goods.