The savings buying offshore would be immense, and we could re-invest that potential expense back into viable, sustainable Canadian industry, or reduce the deficit. (yes I know, dreaming in technicolor.)
The government (of all stripes) has no interest in being competitive, or altruistic. They all share one overriding goal, being re-elected. 170 seats is the only number they pay attention to, and anything that supports their efforts, including how your money is spent across all sectors, to get as close to or surpass that magic number is all that matters.
Canadian governments haven't had a strategic outlook since the late 70's. Rather, it has been a domestic exercise to disseminate favors/largesse to where they think it will bring them the largest return ITO votes/seats. Defence spending has been included in that calculus.
Sigh...
I hear that arguement a lot, and having looked into it fairly intensly, have found it to be unfounded BS, once you consider the economic impact and look at what is actually included in any of these project costs. A big part of the cost is labour, and you can ballpark about 30% of that coming directly back to the government in taxes. So while an experienced yard is more efficient (ie uses less labour hours) at building something then a brand new yard, doesn't take much for that tax offset to even things out.
Sure, there is a learning curve that we're paying for, but there is a really good reason why pretty much the entire G20 has some kind of domestic shipbuilding policy for their Navy; it just makes sense to A) have that strategic capability and B) invest that money in your own economy. We knew all that stuff going into it, so it wasn't an uninformed decision.
If we did a straight commercial contract at an existing yard, there would be zero economic impact, and we'd have increased project management costs for dealing with an international yard. Also, we'd still have to pay for project staff, parts, infrastructure, training and all the other stuff that is included in the project outside the hull, so there would be no real change there. And that approach would not be an apples to apples comparison to the NSS projects anyway, as the contract terms would be totally different.
In the last NSS report, the GDP impact was estimated at $4.1 billion for 2019 (they are based on calendar years, so the 2020 one should be out late spring). Plus this way the gear fitted on it will generally have a Canadian supply chain, which can be a big advantage during actual operation. Even if there were no IRBs or value proposition included, there would still be a big GDP offset by default because they are doing the build in Canada.
For something more complicated like the subs, or specialized like the high speed open ocean ferries, makes perfect sense to look overseas when no one in Canada has the facilities to do it. That's why the 'Build in Canada' policy that has been around since the 60s allows for applications on a project by project basis to do it.
This is specifically a STRATEGIC project meant to create/sustain a combat and a non-combat shipbuilding yard. Sure, it's the distributed economic benefits is a big selling point and all a lot of politicians hear, but it was very deliberately framed and approved by the Canadian government with that in mind, even if that has been lost over time with senior staff turnover.
So does it cost more to build them in Canada? Possibly, but it's impossible to put a number to it (we tried pretty hard), and it's easy to argue that it might cost less once you consider the direct/indirect benefits and spinoffs. That's not even looking at any in service savings/benefits from having a Canadian supply chain.
/endrant
Had this argument many times with bureaucrats from Finance and other departments, and none of them were able to provide actual facts or numbers to back up that it would be cheaper. If you want to get an idea of how hard it is, there was an audit by either the PBO or AG that effectively gave up when trying to find an apples to apples cost comparison on the AOPs.
We include a tonne of stuff in our project costs that no one else does, and have a tonne of extra contract clauses that are unique, so it's almost impossible to get a fair comparison with any publically available project information on any other ship on the planet.