Eric, it's my sense that the 15-minute city might be the most important thing for creating successful mass transit. A 15-minute walk just doesn't take you very far. (There's a pretty cool tool you can use to get a sense of the limits of a 15-minute walk. https://tinyurl.com/3cd252jr) Transit is pretty tough over such short distances. But, organizing for 15-minute walks means creating residential and office density in order to have enough amenities (read neighborhood retail). And, dense nodes create the perfect use case for transit.

It's a virtuous cycle! And, even more so when you add bicycles. (Pun very much intended.)

Yes, definitely. The 15 minute City is intended to be one part of many strategies used to change cities for the better. A 15 min city would enable more robust public transit, and vice versa. Another similar idea/word is "Ped Shed".

Worth noting, a good number of these ideas have been expressed in other ways by many other people, including here in the US by the CNU and others.

I've always been curious to see if there is a path for consistently getting this level of planning into small/medium towns and through the political friction that arises whenever local planning starts to pick up momentum. After all, the root of the word "politics" is "polis", which means city/community.