I understand this from an employee stand point, but from a clinical and tax payer stand point. It holds no water.
No benefit clinically, you've got me there. My county's answer is to put at least two medics on every ALS call, rather than have anyone flying alone. As far as dual role and proficiency, I'll say that a paramedic's education is front loaded, unlike fire, where you spend your entire rookie year studying and drilling. Medics come ready made as far as education is concerned. Let's face it, EMS is only a narrow slice of the medical profession. It really isn't that difficult to become proficient in EMS transport. In fire, to promote, we now need degrees, as well as various classes, such as Officer I,II,III, and Instructor I,II,III. We're taking Pump Operator classes, as well as whatever seminars we can get selected for. Our relevant degrees are in areas such as Fire Science, EMS AAS, and Emergency Management.
The good thing is, we can (we're required to, in fact) drill both EMS and suppression topics on a regular basis. It's not too difficult to maintain proficiency in both disciplines, provided you're in a regular flip flop rotation.
As far as costs, the pro combination argument is that having dual role personnel saves on OT/holdover costs, since personnel are more interchangeable. It's less difficult to fill vacancies. Overall, you'll need less employees in a combined system than you would if both were seperate. In addition, there's much less turnover in a fire based system, so there's less of a hiring cost. The ALS first response allows the department to operate with less ambulances. It would be ideal, of course, to have the EMS fleet upstaffed instead, but it's unrealistic to expect this when most (probably all) single role EMS departments seek to operate with the least amount of units possible. SSM is an extreme example of this (as ineffective as it is).
We can argue that the fire based employees are paid much more than they would be in a non-fire service, but isn't the main complaint in EMS the poor pay? I say that the fire based people have that liveable wage that everyone else (save a few systems in TX and WA) long for. Of course, if you replace a $70,000/yr FF/medic and a $50,000/yr FF/EMT with a $16/hr medic and an $11/hr EMT (if you're lucky) there will be cost savings, but you get what you pay for.
Our medics get $70k/yr after internship, but they can do both jobs. You cut the average career medic's yearly compensation (40k/yr) in half, you have $20k. Since our FF's come out making $50k (figure around 15k of that for EMT, half of an average $30/yr), these salaries aren't really out of line, IMO. Not out of line considering that we work an average 56 hour workweek, 53 of which are straight time per FLSA. For every five employees the county hires, they're saving the costs of two 40 hour employees. So, that $70k medic would only be maybe a $50k medic or less, and that $50k FF would only be a $35k FF. Not so generous when you look at it that way.
This is why I say that while systems in places such as NC are good, the pay still sucks. They're working 56 hour schedules as well (IIRC), so if a medic is only making $30-something a year to start, their hourly is quite poor. I found this out in Charleston SC. I was hired at around $38k/yr on a 24/48. My hourly was $11-$11.50, not more than that. If you're working a 56 hour schedule (48 hour even) and your base is less than 60k give or take, you're getting jacked.