Why do toaster star ratings cluster around 4.2 to 4.5?

Toasters are a mature, commoditized category, and uneven browning or eventual heating-element failure are common across nearly all brands. That pulls most large-volume models into the 4.2 to 4.5 band. A very high average on a low review count, as seen on a couple of newer smart models here, should be treated cautiously until volume builds.