Transportation - The Foundation for Equitable Access to Opportunities

We know that the foundation for equitable access to opportunities is connectedness, the ability to get around. Even if it feels like, compared to your rent or the cost of food, that the fare for the bus is smaller than that, it does add up. New york city has means tested transit discount, 50 % off for people below a certain income, but boston doesn't have that. So why not start there? Why go from zero all the way up to free transit for everybody?