If you are interested in some background, a very detailed dialogue about how Calgary grew and where is here:
https://www.aupress.ca/app/uploads/120152_99Z_Foran_2009-Expansive_Discources.pdf
Amazing that the author was interested enough in this stuff to get into the level of detail they did. I can't imagine anyone else bothered to write all this down and organize it into a narrative. Huge urban development nerd award winner for sure.
In addition to what's been said by others, the utility infrastructure and hills are a very big deal. Pumps, pipes and reservoirs are super expensive and the preference is always use gravity wherever possible. It really only became practical to build at the higher elevations to the West and Northwest once the city was larger, wealthier and had some major infrastructure investments to move the water up the hills. So the patterns of North and south expansion, rather than east and west expansion was influenced by that early on.
Infrastructure has a momentum on this as well due to incremental costs - because we build a pipe or a road in a particular direction, it's often easier/cheaper to keep extending in that same direction. So if a pattern of southward expansion is triggered, it's hard to ever stop it because it's incrementally cheaper to just add a bit over and over again to what you have built rather than build a whole expensive separate axis of pipes, pumps and reservoirs in a different direction.
Same incremental logic applies to highway expansion and other sprawl factors. It's always cheaper to just add a lane than build a brand new train system from scratch. Takes real leadership and major pushes to break this incremental cycle. There's lots of vested interest in status quo and incrementalism too.
Combined with the ever-competing interest of different stakeholders, the outcomes are a city that was incrementally coherent (e.g. it makes sense at the time for each decision given the options of which way to build) , but collectively incoherent (e.g. each incremental decision added up results in a giant car-dependent high cost, inefficient sprawling city).