The steady backlog test is the clearest way I have seen to frame this decision. A fully loaded hire at 134K to 168K only makes sense if there is enough well defined work every month to keep that person on automation, not on whatever else the business needs that week.

The breakeven figure of about 12,500 a month is useful, but I think the more important variable is how well each piece of work is defined. Agency spend on vague requests grows quickly. Agency spend on one clearly stated problem at a time, at a fixed price, stays predictable and makes the comparison with a salary honest.

Your point about handoff docs and admin access is the one buyers skip most often. Whoever builds the automation, the business should own the accounts and be able to run it without them.

The hybrid setup, an in-house operations person working with an outside team, is where many small companies end up, and it is a sensible place to land.