You're making a lot of assumptions that don't reflect how the RCN actually introduces a new class of submarine.
The biggest flaw is the belief that getting the first boat a year earlier somehow solves the manpower problem. It doesn't. It simply moves the problem forward by a year unless the training, maintenance, infrastructure, spares, simulators, documentation, and certification systems are already being built in parallel. And that is exactly the point people keep missing.
Once the submarine is selected, especially if the Korean design is chosen, you are going to see a steady stream of Canadian submariners, engineers, technicians, maintainers, instructors, and project staff going to Korea long before the first Canadian boat ever shows up in Halifax or Esquimalt. That is where the real transition starts. Not on delivery day. Not when the first submarine sails into Canada. It starts years earlier with Canadians embedded in training, construction, trials, documentation, maintenance planning, and acceptance work.
There is also a rumour floating around that Korea may even lend Canada a boat to accelerate crew training. If that turns out to be true, it would only reinforce the point. The manpower solution is not simply “deliver Boat 1 sooner.” The solution is getting Canadian crews onto the selected class as early as possible, building the training cadre, and growing the support system before Canada receives its own fleet.
Your suggestion of “robbing Peter to pay Paul” is exactly what the RCN has been trying to avoid for decades. Strip experienced sailors out of the Victoria class and you've just degraded the very fleet responsible for keeping the submarine service alive. You haven't created people. You've simply redistributed a shortage.
And while everyone loves to talk as if recruitment and retention are in freefall, the reality is more nuanced. Recruiting and retention are actually improving with the new benefits, pay changes, and quality of life measures recently introduced. Is the problem solved? Of course not. There is still a mountain of work to do. But pretending nothing is changing ignores the fact that the CAF is finally starting to put resources in place to keep people and attract new ones.
The manpower challenge isn't caused by delivery schedules. It is caused by trying to grow from four submarines to twelve while sustaining the boats we already have. Delivering Boat 1 in 2031 instead of 2032 doesn't magically produce hundreds of submariners, engineers, technicians, and maintainers.