I scaled to 30+ people with automated administration. My cost was under $150 a month for everything we needed to run a successful consultancy and product business. Our accountant was blown away by how simple his life was.
I'm constantly amazed at how it has gotten much worse in the resulting decade.
E.g traditional automation + humans handling the drag = $4,000 per month with a couple of known blunder each year
vs traditional automation + AI = $400, with unknown number of blunders.
Of course it depends how much a blunder costs, to solve, or swallow. But I would bet that accounting errors even for a small business would cost the business on the long run. And that's assuming we don't yet have adversarial behavior which we can expect to come from both the inside and the outside.