As I said earlier, in the past, Canada Post was a department, the Post Office Department. It was close to the government, because it has always provided an essential service for the population, just like health services, road maintenance, and so on. It is an essential service.
Would there be a cost to guaranteeing home mail delivery to seniors? As you said, this is subsidized. If there is a cost, it would have to be subsidized. Seniors who like myself do not have special needs would not be entitled to home mail delivery.