So I've seen this argument made before, but they never seem to explain convincingly enough why that sole technician (or small group of technicians) would be paid so handsomely.
In a market in which there's a glut of labor, wouldn't there be plenty of desperate, and very capable, workers competing for the few available positions, thereby driving down the wages for those positions significantly as well?
Which specific industries are these which currently have a fleet of robots and 0 technicians?
Unless you mean that it would have the capacity but would be told not use it in this specific situation. It can't be programmed deterministically, and getting it to never do this emergently would take significantly stronger guardrails than anything even the frontier labs have been able to put together.
You pay the one technician $200k instead of $80 because that technician has an outside option that will pay him $199k. He has that outside option because everyone is automating their warehouses and factories and stuff, and so in aggregate we basically wind up with 6 times as many warehouses and factories each employing 1 person.
It's a little more nuanced. There is not infinite demand for warehouses. So some of what happens is an $80k/year warehouse worker becomes a medical technician making $90k/year providing non-automatable services to the warehouse guy making $200k/year -- but the general story is everyone's wages go up. And history bears that out.
Why not paying the technician $80,000 a year?
Because every other company has also replaced their 6 warehouse workers with a fleet of robots and 1 technician, and that technician's skills are more rare and specialized than the warehouse workers, so you're competing with every other warehouse-owning company to hire that technician, so that technician can demand a higher salary. In other words, capitalism.