They’ll have some very general specialists that basically know where their expertise stops and when they need to bring in Mounties.
One of the problems that existed in Ontario wasn't so much the operational folks recognizing the need to call in the OPP (or even another large municipal service) was the political willingness of their command. After the changes to Police Services Act in the mid-1990s downloaded policing costs to the municipalities, those that already had or wanting to create a municipal service had to show that they were 'all singin'/all dancin' services to their civilian leadership and taxpayers to justify their existence. Some wouldn't call for help until it was far too late, some even never. The OPP has no 'white knight' authority - they have to be either asked or directed. The Minster or local Crown can direct, but never do.
Until costs were downloaded, most municipal governments never had to deal with such matters. I recall one small municipal department who sent one member on a containment course then proudly announced to their Board that they now had a hostage team. In another case that I was involved in involving a homicide, they had to wait until the chief went on vacation before the 2 i/c could call us in; the chief hated the OPP and wouldn't ask for assistance even knowing that they were clearly in over their heads.
From what little I know of it, I am also intrigued by the 'Quebec model'. I have no clue of their municipal/provincial funding arrangements. It is often easier to have a prescriptive public policy when it is accompanied with bags of money. To say that police service X is responsible to assist other services implies that they have the funding and staffing to do that. For the smaller provinces such as Atlantic Canada, some services, such as 911/call taking could be absorbed at the provincial level and more operational matters such as forensics, major case management, etc. centred on existing large municipal services (again, provided they are funded and staffed for it). In addition, the costing has to be addressed by policy. A small community would be loathe to call for expensive assistance if they know they are going to get stuck with a bill.
This is similar to the historic role of the London Metropolitan Police. Even though there are basically and municipal police service, they have historically had both extra-territorial and even international responsibilities. Most of that is gone now but certain elements still exist.