Around here, fire departments are the primary EMS agency. Probably 2/3 of the departments run rescue ambulances (RAs), while the rest run non-transport squads with a private company providing the transport. The private companies primarily do inter-facility transports or provide transport for the FDs, but don't respond as a primary provider (and most are BLS as well).
We support about 11,000 residents, and a large percentage are elderly. We really don't get that many full arrests outside of the skilled nursing facility (where many are DNR anyway), but this past month we did.
As I said, most departments are ALS...we're the only BLS department in the county (we're also the only volunteer department). Arcadia, our neighbor to the south and east, has three stations and runs two ALS RAs. Pasadena, to the west, runs 4 ALS RAs and two ALS engines. Their EMS call volume is high enough that it's impractical for them to respond outside their own jurisdiction, especially coupled with the current hospital crisis in L.A. County. It's not uncommon for an ALS unit to be out of service at the hospital for over an hour waiting for a bed for their patient...recently, 3 RA crews from two departments were out of service for close to three hours at the same hospital...a BC finally had to come in and have one crew take all three patients to put the other two RAs back in service.