I don't understand how commuters into Toronto save money by driving in from Port Hope, Peterborough, Barrie, Grand Valley , Kitchener , Hamilton and St Catherine's . They also loose 2 to 4 hours of their life in the vehicle every day.
Various reasons.
In many sectors (outside of govt), people change jobs/companies every 2-4 years. Some are stuck with ever-changing short contract jobs. Job instability in other words.... it's the new normal. So while living near work is ideal, for many people that means constantly moving - some people chose to stabilize their home location and just drive as needed.
As with many things, if you are wealthy, then you have more choices. Plunk down $600k+ for a house in the GTA, or at least buy a condo for the Monday to Thursday nights you need to stay in the city. Many people don't have that choice available. If you take on the larger mortage to live in the city, you end up burning the commuting time you've gained working side-jobs to pay the larger mortgage - most of us peasants won't gain time that way.
For the right job, I'll make the drive. I used to get to my office in Mississauga on our weekly meeting day for 6:00am (my choice), put in that day at the office and seeing nearby clients. The other 4 days were spent seeing clients. A lot of driving, but it was varied, and to a sizeable extent, outside of rush-hour(s).
Not for everybody, but I'd do it again, for the right price

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But yeah.... that actually circles back to
Why Diesel ? It's always made more sense (operational $ terms) to high and ultra-high mileage drivers - at least in Canada.
Last I checked, a tdi will beat most hybrids, in steady/continuous highway driving.
When I first worked in Etobicoke, there was an engineer that commuted daily from Trenton. That's about 180km one-way; a bit high even my my standards !
Rgds, D.