We always look at NATO. Take a look at Australia, Japan and Korea for other comparables. Then you need to compare what the "frigates" actually are for capability. Some are short range national water types of ships.
Australia is a good comparable, however their requirements have them worrying about the sea/air gap north of the continent, and their requirement to maintain a health amphibious capability. Japan and Korea like most of NATO only worry about domestic water deployments close to home. France and the UK have plenty of long range colonial remnants that they need to pay attention to.
Right now the Canadian doctrine as presented in various policy documents are that the RCN needs to maintain one task group consisting of an AOR, 3-4 destroyers/frigates, with add ons.
In order to do that 15 destroyers would mean we have approx 4-5 destroyers available at all times. So that part of the doctrine is covered off. Following on from that we would want four JSS/AOR's to provide one available at all times. That fills out the core capabilities of the task group.
I deliberately limited the scope to NATO, as Canada has an alliance with NATO and I wanted to compare with other NATO alliance members.
Your point though is very well noted ... albeit I don't think anyone needs a forum post by me on army.ca summarizing all nation's frigate/destroyer count, especially given such can be deceptive given a navy's balance between quantity of submarines, patrol boats, corvettes, frigates, destroyers and larger capital ships - all of which can be different from navy to navy - not to mention geographical differences of countries.
Still, limiting the scope to frigates and destroyers, given that you mentioned Australia, Japan and South Korea, I note:
- Australia (RAN) = ~10 frigates/destroyers ( 3 x Hobart class + 7 x Anzac class)
- Japan (JMSDF) = ~50 frigates/destroyers (with 36-40 Kongo, Atago, Maya, Murasame destroyers) + ( ~10-12 Mogami class)
- South Korea = ~31 frigates/destroyers (13 destroyers across KDX-I, II, and III, plus ~18 frigates across Chungnam, Daegu, and Incheon classes).
... where, for example, Australia has major changes coming and those numbers are deceptive.
Your comment about 15 destroyers likely means only 4 to 5 available, at all times, which is something I also note to be generally true. I think all navies "suffer" with that limitation, albeit the numbers can vary from nation to nation from time to time.
These are interesting times for the RCN, with challenges ahead to procure both new ships, submarines, and the sailors to man them. Similar to what I believe all in this thread wish, I too wish the best for the RCN.