Public transit is not free where I live. I think there are two aspects to this matter of whether or not it should be free, or at least subsidized a little more. The video primarily addresses one of them, which is what the implications are for those with low income.
But the other aspect has to do with what it would take to get people who drive everywhere today to leave their cars at home and take transit instead for routine travel like commuting. I've done the math on this in terms of my personal monthly budget. In an either/or scenario of taking transit exclusively with no car ownership, there is no question that public transit is far more affordable. But once you have taken that leap and bought a car, it is no longer the slam dunk in favour of transit. What I mean by that is if you own a car but take the bus to work every day and only use the car for occasional errands that necessitate it, you will not necessarily be ahead financially at the end of the month.
At least not in my case. Some things could affect this calcuation. For example, if I had to pay for parking where I work, transit would almost certainly win. But it's a shame when I think others are likely going through the same calculations and drawing the same conclusions, leaving ridership numbers low and streets clogged with automobiles.
What I eventually concluded was that a third option—investing in a ebike for commuting/light errands—was indeed a slam dunk budget-wise, so I have gone with that. I still need to have a car at my disposal for certain things I do, but it stays in the driveway 80% of the time, and beyond the upfront cost of purchasing the bike, its operational costs are very close to zero. So it's basically free transportation once you've paid it off, and that is quite compelling to me.