Calgary Handibus Association is a charity (not owned by anyone but its membership). Until the creation of Access Calgary, CHBA's funding arrangement required two city representative on the board of directors. Their buses have been displaying a decal stating something like "funded by the City of Calgary" since the mid 1990's.
This interconnection sometimes creates the notion that the City calls the shots for CHBA as it would for Calgary Housing Company or Enmax
As to why they are turning away from being a busing contractor, I refer you to their media release
http://www.calgaryhandibus.com/news/news
In the charitable sector, there is a growing realization that charities have to be cautious about competing with similar entities (i.e. competing against other charities or even competing against the commercial sector). My interpretation of the release is: After 40 years of service, CHBA sees less of a need for a charity to provide the front-line transportation (as a contractor) when there are many contractors willing to step up.
From my view on the sidelines, I think the City would be better off in the long run by bring the larger buses (similar to what Calgary Handi-bus Association uses) in-house.
Deeper pockets to pay the specialized bus drivers, better communication between scheduling and driver (schedulers cannot talk directly to drivers in a contractor model) are some of the benefits. The City- run buses form a backbone of service hours and other contractors would carry the rest.
Red Deer and Lethbridge, brought their local charity operated buses in-house over the past decade (or so) -- it is not unusual. There once was an Edmonton Handi-bus Society... which dissolved when the city implemented commercial bus contractors. Then, around 2003? Edmonton brought the contracted buses in-house as a backbone of service (95 buses).
industry rumor:
Access Calgary was very surprized by the CHBA decision... but that is just a rumor