Aside from the amazing Raspberry Pi ecosystem, the big appeal of this chip is for gpio-heavy applications that don't need wireless connectivity. If you need wireless you'd want an ESP8266 or one of its siblings. Of course the history of the Pi Zero and the Zero W suggests they might release a connected version in the future.
What if mid project you realise you need more I/O? If you choose stm32 for your project you can just choose bigger controller, then you can easily even run your own board. It seems like RPi starts building a walled garden. Not cool.
Also note that there are a number of other integrators (Sparkfun, Adafruit, even Arduino) who are making custom boards. I wonder if one of them may even hack in some sort of wireless module.
