Now, I'm just a street medic, you obviously know WAY more about this than me, so it's possibly you'll tell me I'm completely wrong and I'll just accept that.
It seems to me, though, that a county department could easily underbid (and still remain profitable against) a private company for any contract they wanted. Now, granted, AMR is the extreme example of "private company", but still, a county department has a bunch of the support structure that they have to provide no matter what
The flip side, of course, is that AMR could always bid at a loss, but I don't really see that happening, though there could be political payoffs that I'm oblivious to.
okay, bear with me here its 4am and I have been awake for 36 hours. I will attempt to stay on topic and keep spelling and grammatical errors to a minimum. but the question you ask has far too many facets to even attempt a cohesive written response.
you are not "Just a street medic", you are a Paramedic. and you are correct that a county department could bid lower than AMR based on their size (in business its called economies of scale). however AMR or Envision Healthcare, the parent company, has a much larger benefit when it comes to economies of scale because of the vast size of the company and how much stuff they purchase yearly.
the following numbers are arbitrary as I have no clue what the real numbers are.
here is an example AMR and SBCO both put in an order to McKesson for a case of gloves and 4x4's. because SBco may only order 100 cases of gloves per year and 10 cases of 4x4's McKesson bills them $3000.00 and then $50 for shipping. however beacuse this will be just a small part of AMRs order for the year lets say 10,000 cases of gloves and 1000 cases of 4x4s AMR will be billed at a negotiated rate of lets say cost +10%, or $2000.00 for the same order that the county placed because the supplier knows that AMR will order more and they want to keep them as a customer. the same goes for ambulances... AMR pays much less than anyone else for the same stuff because of their purchasing power.
then we have to look at the personnel cost, lets assume the county will run the ambulances with non-union, non-classified, non-firemen with the same hourly rate as AMR, the overhead staff needed by the county would cost considerably more than AMR because they would have to up staff HR, and Administration to accommodate the approximately 1000 new county employees, whereas AMR already has the HR and Admin staffing for 18,000 employees the 1000 or so berdo employees are merely a drop in the bucket.
and then finally we run back into the anti-trust laws, its illegal to knowingly bid at a loss for the purposes of underbidding. working for a loss is not sustainable for the county unless they plan on subsidizing the cost with increased taxes or special district fees which I doubt the voters (ie, tax payers) would approve of.
so to answer your question, in theory yes the county could possibly submit a bid that is lower cost but in reality there is no way the county could operate at a lower cost.
now the plot thickens with one last detail, a competitive bid does not necessarily mean the LOWEST bid, it means the BEST bid. It is the county board of commissioners who decides what is BEST bid, not the fire department. Now I will say that bribery is illegal and AMR would never do that... but making campaign contributions is not illegal, and AMR loves to support politicians....
one last tidbit in support of AMRs political machine.
I think it would be interesting to know who tipped Dr. Backer (CA EMSA Director) off to OCFA and their "bidding process" for ambulances in which the highest ranked bids some how don't get selected. seeing how Care who may or may not have been the benefactor of these "competitive" bids, was recently bought by Faulk AMRs biggest threat, and AMR recently bought Doctor's ambulance which happens to be one of the other two ambulances who could win the new bidding process if controlled by the county... and does anybody remember that silly bill that the firefighters tried to get passed that would require private employees to remove all county names from their uniform? yea that didn't pass either, oddly enough it was the OCFA union that wrote that bill... how the world turns...