I honestly don't know how often I have to say this. Those issues are about Oxford's traffic scheme, not the 15 min city concept.
It doesn't rain where you are? There aren't disabled people?
So the Oxford scheme isn't what you mean, and the Barcelona scheme which you cited, is nothing like a "15 minute city", it's a wide pedestrianised street - with a couple of short extensions.
I asked for examples and you can't show me
one?
Barcelona has vague plans for "tiles".
Utrecht is vaunted as a 15 minute city but it isn't, except maybe a tiny part. Look for primary and secondary schools, hospitals and the rest which are missing.
No cars, it says. Use Streetview - cars al over the place, shoehorned in, so the peasants are revolting. Ooops. As I suggested above, I can't ride a bucking fike, so I wouldn't be able to go out.
Bad luck for you if you get a problem and they convert your suburb. Would you be so keen, then?
"Let's have everything really close" sounds great. But you don't achieve it by restricting mobility to bikes and sticking a couple of shops in. More public transport might be good, but who pays? It could never come to 15 minutes of me.
Oh but it's not that, it's not this. So what is it? A partly formed concept, as yet illusory.
There are, I just read, 16 "partially implemented" trials worldwide.
So there are people paying lip service to the vague idea, but nobody actually taking it seriously?