This might be giving away some secret of sorts but here we go:
Sarasota is a unique place.
Goodwill maintains dedicated bookstores - selling books at $2 each. Needless to say the stores are always well visited. There are always new amazing books streaming through. I once met a young bookseller lady from Houston who drove all the way to fill her truck with books from here.
And, as the article hinted at, the area itself acts twofold: as a magnet and a filter. Being an artsy famous cultured beach town it attracts the often rich and successful retirees who, after having spent a life of collecting books but then because of age and many moves having to narrow down their collection end up with the best of the best books on any topic thus singled out and neatly brought to Sarasota. When these fine folks pass away they leave the treasures for the rest of us (unless their children have any idea what they are just about to give away). So, very often, you would bump into a new book, look at the artful ‘Ex libris’ sticker left on the first page and realize another collection of someone interesting just arrived. To honor those I usually try to pick up all their treasures and add them to my own collection which the kids have been instructed to keep together and hand down over the centuries…