I wrote a book called “Crap Towns”. It seemed funny at the time

The problem is those towns weren’t crap within living memory when the books were written. Now anyone who remembers otherwise is close to dead

Some of them maybe have gentrified (not to ignore that this in itself isn't 100% a good thing). Others are if anything worse than when he wrote the book.

Nah, several of them were always running jokes, some of them were a lot worse a decade or three earlier, and some of them were picked far more for their snobbishness or for being homogenous sanitised suburbia than their decline.