Who maintains community/cluster mailboxes in Canada?

Canada Post, to lower costs, forced a shift to group mailboxes for neighborhoods.  This was criticized for a couple reasons, one being wrt historic neighborhoods, the appurtenances aren't particularly fitting architecturally.  

Suburban and new subdivisions are outfitted with the group mailboxes and have been since the 1980s ("Super mailboxes, 'second-class citizens' and mail inequality," CBC).

Thus far, city neighborhoods still get door to door service ("An opportunity — if Canada Post chooses to take it," Winnipeg Free Press).  

Back when the change in how to deliver mail was first contemplated, wrt snow, another point was raised that one of the motivators for people to shovel their sidewalks was so that mail could be delivered ("Canadian Postal Workers Battle to Save Door-to-Door Delivery," Labor Notes, 2014).

Here, it seems that Canada Post doesn't take responsibility for snow clearance around their group mailboxes.

Image from "Canada gets cluster-boxed: Why it can’t happen here," Save the Post Office.  This article also discusses calls to create similar cluster boxes or community mailboxes in the US.

Another issue is general maintenance, such as dealing with people discarding mail at the box.  

Apartment buildings without front desks often have a mass-mess of discarded mail on the floor below the mailboxes.  This can be an issue in Canada too.