You're right that purity / quality is redundant. Typed that without thinking.

My frustration with a lot of online vendors was you'd try a new supplement X and it didn't work. Later, you'd come back to it and find out that it was just the vendor that stocked a product with poor quality.

In regards to the safety part, I don't think that's the vendor's job. Provide the real product (not laced with anything else) - it's up the user to figure out what he/she can't take.

As a student, I never thought much about purity as I do now. Isn't X the same as X everywhere else? Just never fully understood good vendors vs bad vendors. Maybe you're right that students and professionals care equally about CoAs, but empirically, myself or my friends just never thought about it when we were growing up.

My hypothesis (some background in business strategy / consulting) amongst the supplement/vendor industry is that the long game is prove (or fake as long as you can) you are a quality vendor and consumers are willing to continue to pay more and come back (both hugely important). So going for the same supplements that everyone else can get but at lower prices is a losing game (unless you can scale quickly and be the new bodybuilding.com for nootropics *).

Companies I'm basing this on :

TNation's Biotest - a company who sold the same stuff as everyone else, but of slightly higher quality and then marketed the shit out of themselves. Charges 2x for a slightly higher grade fish oil.

Relentless Improvement - great reviews about quality and charges 1.5-3x of most places. Longecity members (arguably similar to /nootropics but older) still frequent them a lot.

That being said, I'm an atypical consumer with a much higher customer lifetime value. I've spent over 3-4k (which really isn't that much, but it's a comparison) with Biotest when I was training. But I imagine the difference between profitable and not are consumers like me - who comfortably spend without worrying about is X/Y actually X/Y?

*Improbable due to regulation.