At the time I wrote the post, October 2017, this was the situation. We now know
that there are SP3's in the US with this issue and that Microsoft has not
acknowledged that these are anything but individual system failures. They have
not acknowledged any trending or commented on the cause.
Barb, I am facing the same problem for months, but I found a different behavior in terms of workaround.
I realized that when the keyboard is not working (surface type cover), if I remove it from the surface and after that remove the surface from the
outlet power (meaning that it will be running in the battery), than reconnect the surface type cover, it its back working.
It's still an issue but has a workaround. Anyway, I hope that Microsoft fix this, since I also agree that is unacceptable to pay more than USD
1.500 in a device and having this issue without any answer from a giant such as Microsoft. I also replaced my keyboard (USD 93) thinking that the problem would be it. And along this journey, the power supply (USD 70) also had to be replaced, since Microsoft
created it to be replaced. The cables are so thin, that with the regular use, they break and stop working.