If you want flexibility then you cannot use silicon.
Who said anything about "flexibility"?? I'm talking about reliability and longevity. "If" the "plastic circuit" pushers can actually DEMONSTRATE the such circuitry has equivalent long-term reliability to silicon, then I'll be interested--otherwise, it's only good for the "use it once and toss it" applications.
As a chemist, I know how SHORT the useful life of most plastic products typically is--eco-propaganda to the contrary.