My thoughts of such a purchase would be that Canada could have its own production of such an aircraft not subject to foreign interreference in upgrades or usage
The practical problems with that is that any Canadian order would be rather small, so that the costs to setup the production facility would increase the costs per aircraft. Making this even worse is that the production run would also be fairly short meaning that after a few years the production line would stop and the facility would either close or need to be re-tooled to do something else, which in turn would mean that after a few years Canada would not be able to order more domestic production.
Also, trying to run a small fleet of well, anything really, and keep them upgraded can get quite expensive, especially if any/all upgrade programmes are only done domestically as opposed to part of a larger overall upgrade path or spiral development. If Canada were to start operating the Rafale for example, with perhaps 40-50 aircraft, and want to manage aircraft upgrades independently, that the costs and technical requirements to do so would be solely burden Canada. As expensive as some of the updates and upgrades to aircraft like the P-8 might be, the per aircraft cost for some of them is not really all that high, because at this point there is close to 200 aircraft in service worldwide.