That literally defeats the entire purpose of the 15 minute city.

Not if the purpose is literally just to put everything in walking distance so most people can choose to meet their needs locally. 100% adherence isn't required, there is no chain reaction if there isn't a perfect success rate. I don't know why you insist on assuming top-down control that grips tighter and tighter if there's any deviation from the plan. I've told you I'm talking purely about infrastructure and incentive, a voluntary system that uses urban planning to encourage trends, not enforce adherence.

Yes, it's trickier doing it with urban planning rather than in separate small communities, and probably the biggest hurdle is making sure people are able to be employed locally. There's no perfect answer to that, but the ability to work from home helps.

I'm just saying if it's voluntary and not authoritarian, there are many potential benefits and few meaningful downsides. It would be an experiment worth trying if enough people were on board and enough resources were available. That's all hypothetical of course, but it's not an inherently awful concept.