Is public transportation more efficient per mile/person? Yes. Does it solves all the transportation problems? No: it's not covering even half of our needs. Just for reference: only 30% of NY population is using mass transit for commutes. SF is just 15% [1]. And in most areas in the country you can't go and buy some food if you have no car: there is not even a sidewalk, not to mention public transportation. So what you are proposing is to additional burden for the majory of the population for "storing their property" without providing any alternative.

Edit: who pays majority of taxes for road use? It's car owners. You have cheap buses only because car owners paid majority of the bills for road network maintenance and development.

[1] https://en.wikipedia.org/wiki/Mass_transit_in_the_United_Sta... [2] https://taxfoundation.org/state-gasoline-tax-rates-2017/