I will hand it to Calgary though. Reading around, it does look like the job density is in the central business district is exceptionally good for such a late-developed North American city. The park and rides don't dent housing sprawl at all, but at least they allow people to commute to the same place. Hopefully that does create demand for dense housing around the central business district eventually.
I think at this point we also need to massively raise the gas tax, pay it back as a universal dividend to avoid right-wing revolution. And simultaneously, we need to build a bunch of transit so people trying to win the gas-tax-dividend arbitrage have a valid strategy. Make the demand, make the supply.
Our political situation doesn't allow for that, but I don't really see the choice? Trying to electrify all the cars is perhaps easier on the American psyche, but much less efficient, and will not help with all the non-global-warming major externalities we need to fix nearly as urgently.
It should also be noted that Calgary faced similar challenges to SLC, and they optimized for it in similar ways: optimizing for total system length and highest frequencies per dollar spent, and often developing suburban park and ride stations. And over the last 40 years, Calgary has become more dense as a result. It has become one of the highest ridership per mile systems in north america, better than any in the US, besting even a 125 year old line with significant subterranean sections right through the dense core of Boston.