There is no value-add to hiring software engineers to build basic apps. That's what AI will be good for: repeating what has already been written and published to the web somewhere. The commoditized software that we shouldn't have been paying to write to begin with.
But AI won't help you with all the rest of the cost. The maintenance, which is 80% of your cost anyway. The infrastructure, monitoring, logging, metrics, VCS hosting, security scanning, QA, product manager, designer, data scientist, sales/marketing, customer support. All of that is part of the cost of building and running the software. The software engineers that churn out the initial app is a smaller cost than it seems. And we're still gonna need skilled engineers to use the AI, because AI is an idiot savant.
Personally I think 50% cost reduction in human engineers is the best you can expect. That's not nothing, but that's probably like a 10% savings on total revenue expenditure.