Replying to myself as a followup:
https://digitechcomputer.com/costs-of-ems-readiness/
Looks like of the $1954 they estimate for a transport (already quite a bit below TFAs $2673), $1582 is salary. Given that we established the crew in the ambulance are taking home about $140 per transport between them, this seems bonkers. Capital, medical supplies, and fleet maintenance are a whopping 6% of the "cost".
As far as I can tell, your article is talking about total salary cost, divided by number of rides, not just the amount that the ambulance crew is being paid during an actual trip.
For that, $1500 seems pretty reasonable. In a place like the US, labor costs often dominate the total cost of many goods and services.
And remember, you have to pay the staff while they are sitting there waiting for a call that may never come. According to the OP's article, the ideal utilization is 30-50%, because you don't want a situation where there's a surge in requests and you don't have an available ambulance. So you're paying people to sit around and wait for a call, and, under normal conditions, you'll have 50-70% of that pool of people not ending up needing to take calls at all.
Also your article includes under salaries:
> Regular, overtime, vacation, and holiday pay for all EMS staff, including EMTs, paramedics, chiefs, 911 call technicians, dispatchers, and support staff
That's not just the 2-3 people on the ambulance during trips. That's a lot more people required to make the entire system work.
You need more than the crew in the ambulance.
Dispatch, maintenance, janitors, HR, managers.
They also need continuous training, and that is also a large salary cost for training staff (you have to pay them and the trainer).