I never said the chip manufacturers were device manufacturers, perhaps you read that incorrectly?

The companies that deploy a TI, Nordic, Broadcom chipset are subject to the scrutiny I just mentioned. The chipset manufacturers offer reference designs but generally you need a custom matching circuit and a complex RF design to do it correctly. That's where most manufacturers skimp out because its generally "good enough"

As for WiFi, it does not frequency hop but is capable of "auto" selecting a channel on boot (generally).