Downstream innovation takes an existing normalization of truth and optimizes its delivery in a spiraling sub-optimization of value and/or price. Upstream innovation, unaccepting of the truth mentioned above, invents a higher and better normalization of truth-inducing premium value, from which eventually a plethora of downstream evolutions and copycats arise. A process of relativity identical to the hydrologic cycle in nature.
So, how you innovate depends on where you enter the cycle, upstream innovation requiring prime risk and money and defiance of the norm, downstream innovation soon wallowing in subprime risk, and capital in compliance with the norm. The latter turning into a dead-end street until obliterated by upstream innovation.
All-in-all a never-ending cycle of opportunity.