The average family isn't that spread out in their work-life habits as you make out. Most cities have an urban core where most commercial enterprises are, and mo

The average family isn't that spread out in their work-life habits as you make out. Most cities have an urban core where most commercial enterprises are, and most people commute into that area. The vast majority of Dublin City Council (population ~600,000) is <15 minutes away from the city centre by bicycle. As such most people are within a 15 minute journey of most places of business that they could need, and most workplaces. Little work has been put in to make it this way, it's just a consequence of being an old, dense urban core. By contrast, people who live in the surrounding suburbs have woeful commutes that only make sense by car. This is a consequence of building sprawling cities - it's not some innate fact of life. Developing dense cores that people commute to from relatively nearby areas results in short commutes for most people and makes active travel feasible. One core serving an ever expanding catchment area results in long commutes pushes people into cars. Regardless, the main point of "15-minute cities" isn't to solve everyone's existing commute. It's to develop areas so that all essential services are available by active travel. It's to make shopping, education, healthcare, businesses and leisure accessible so everyone has the option to conduct their life with less travel, as opposed to a model where a vehicle is strictly necessary.