True: Drafting a guy is an investment of significant capital (especially for a guy like DK, who will go 1st round, by nearly all accounts).
True: OP stated that Duke is better than any draft prospect WR in this class.
Where this argument falls apart is the investment side. We've invested next to nothing on Duke; whereas, were we to pick up DK at #9, or trade back into the teens to nab him, THAT would be a major capital investment. Part of the reason it's such a major investment is that you know you're drafting a guy in his early 20's (unless it's a BYU kid or a military service situation). Part of the reason we spent chump change (not the whole reason, BUT I'd argue a significant element of that reason) is precisely what you stated: Duke is 25.
What I'm saying is that you're comparing apples to transmissions... different circumstances; different expectations; different sunk costs; different expectations.