And as I understand it:
New terminal = investment by the airport authority
New navaid = cost to NavCanada
Considering the transition to RNAV GNSS approaches, there's going to be very little appetite to invest in net-new ILS equipment, even though a large fraction of commercial aircraft in Canada cannot perform precision GPS approaches.
Around 1998, Nav Canada conducted a cost-benefit analysis concerning the installation of an ILS for runway 05 in Halifax. The request came from an operator who's 767 suffered a major tail strike a couple of years before, that cost 10 million dollars to fix. That was due to crossing the FAF at the minimum crossing altitude, giving a flight path angle of about 1.2 degrees to MDA, and coming in a little slow near the VRef.
The result was that Nav Canada's cost for an ILS would have been about 2 million dollars, plus another 2.5 million to the Halifax Airport Authority for upgraded approach lighting and landscaping, because the localizer antenna would have to otherwise be placed in a ravine, and there was a service road where the glide-slope antenna would be situated. Both agreed that the cost-benefit was positive: 4.5 million dollar investment compared to another potential (or worse) 10 million dollar loss to an air carrier. The airline in question balked at being responsible for such an outlay, despite the fact that they understood that the system would pay and not the airline directly. Nav Canada put the project on the back burner due to lack of airline interest.
Typical of airlines in Canada, at least at the time: our pilots are heroes, except whey they become
when they crash an airplane.