I gotta agree with FlyingDick on this, DeMichael. With all due respect. Those market items seeded by the NPCs are a minority of all items on sale, and as I’m understanding you can’t turn profits on any of them. (For simplicity’s sake I am talking only about market items here in this discussion, not about rat drops, or hacking loot, which, technically are also NPC-origin items tradable on the market).
So what are we talking about here exactly? Some trade goods are seeded by NPCs. What are those – Wheat, Antibiotics, Frozen Food – just as a few examples. None of these are used for anything in the game, other than just for keeping them in your hangar for roleplay or just because you wanna own them. Their supply is technically infinite, they’re cheap, and they have no value in the game. Most importantly: You can’t sell that NPC item back to a player for more amount of ISK you used to buy it or generate new items from it for profit.  This is what makes them worthless in terms of market viability.
Skills, yes skills are more important and they’re seeded mostly by NPCs, but I believe there’s a good reason for that – to avoid a situation where some player-run corporation or an alliance will profit from something that should be a free right for every EVE player – free access to skills (not free as in not costing anything, but free as in it will always be available in the game). Again, you can’t sell an NPC-seeded skill back to a player for more than you paid for it. Making it worthless with regards to trading.
Blueprint originals – now this is the most important thing on this list, in my opinion. You can buy BPOs from NPCs and turn a profit on them. So this is where DeMichael’s point is most relevant. But, again – you will only turn profit on modified BPOs, not on 0/0 NPC-value BPOs. A researched BPO is no longer an NPC item. A player has interacted with it (making any subsequent activities with it PVP). Most importantly, you can’t sell the same unresearched BPO back to a player for more ISK than you paid for it. This is a defining feature of NPC-seeded items. You can’t profit on them, making them worthless for trading.
Have I left any of the NPC items out that are relevant to the point? DeMichael Crimson – I don’t mean to start arguing with you, we’ve respectfully conversed on these forums before and I hope that can continue even after this post. If you have any specific NPC items in mind with regards to your point, then I’d like to hear which ones specifically you meant. I’m genuinely interested as I am a trader and maybe I’m not aware of all the NPC market items even.
My point being – yes NPC-seeded items exist. You can buy them and own them. But you can’t generate profts on those items. Market may not be PVP-only in those terms, but trading is. That’s the difference.