Depends on where you live. In most of Europe, trains are frequent and direct between city centers.

My parents tend to prefer the car for the 3-hour trip (also 3 hours by train and bus) to Grandma's when at least 3 people go because it's cheaper. A higher toll on the highway could change the threshold, and we'd go more comfortably. Politicians can smoothly adjust the number of people for which public transport wins out with taxes and investments. You're more likely to cling to the car and they've accounted for that in their models, maybe making you switch for a specific kind of trip is not worth the investment. There are lots of factors, such as political alignment, culture, wealth distribution, existing infrastructure etc. that make some jurisdictions able to move the threshold faster than others. Still, the majority of people using cars is unsustainable for lots of reasons:

• noise, smoke, particulate matter pollution
• high energy use per unit of distance per person regardless of drivetrain and resulting climate change
• cost of road maintenance
• waste of space for parking, resulting in poor land use and sprawl
• accident fatalities
• unwalkable areas ruin business opportunities, resulting in towns that simply go broke

so there is an obligation to eventually push the threshold in favor of public transit for most trips.