Were you expecting Cake to install the software and hardware?
Were you expecting Cake to write to play your music?
Nowhere does Cake state they should do the configuration for you. Absolutely nowhere. None of your references or quotes say this. You seem to think "configuration" comes under terms "certification" and "testing". Nope and no. Eggs are not sausages.
Configuring and optimizing a PC is YOUR responsibility. YOU are the integrator. Cake is NOT responsible for your hardware unless they make it. You get the software and tools to do it from various companies who have supplied it, YOU have to do it.
You still didn't answer my specific questions either...
a) Does Dell supply device drivers or test your audio equipment?
b) Does HP test sonar on their machines?
c) Why do Dell and other manufacturers issues firmware and BIOS upgrades?
d) Why does windows have registry tweaks?
e) Why does MS supply windows update?
f) Why do people leave stability and optimization tips?
I guess it's for magical reasons.