[bumby]

If you automate everything, how is profit made?

I think profit is a different issue. Profit is not necessarily dependent of automation. Automation is just a means to reduce human labor. Generally, this increases efficiency which leads to increased productivity, but it's definitely not the only way to improve efficiency. There are other ways of increasing productivity and I would argue you will never have completely efficient processes. And innovation is always a potential disrupter to generate new profit.

Even Marx said it's just a tendency for profit to fall and not an absolute maxim.