I've bolded part of your post which I don't understand how it relates to the topic of manager greed at all, though it does present the question: Do players not appear on the negotiations list if they are in the starting eleven?
Besides that, your way of thinking comes across as greed to me. Firstly, of course we won't sell the player if we still need them, so now the focus shifts to players we don't need. I'm happy to settle for just a token or two from negotiations. If I were to sell them on auctions, I would just get money and no tokens, so any tokens on negotiations can be seen as a bonus, the money is not as important for me.