Same reason we love to sell to them.
For the most part not as a whole, new member son ebay do not have much to base their purchase or bids against. They are inexperienced to the value of the items.
So when you are a seller a new person can bid up the value of an item well beyond the value and amount they usually sell for. thus making a happy seller.
On the flip side. If you find yourself in a bid with newer people the only thing they have to justify thier bidding an amount is thatthey have the money to do it. So although that item you find is in perfect condition to place in your collection. The new person sees it as a playable item in perfect condition.
They view it as a means to regain a lost item of their youth and not as the value of the collective piece. So as you see it may be only worth $20.00 as a collectible or possibly $100.00. Yet te new person may be saying to them it is worth $500. so you have to pay maximum amount fo the item, or lose it and hope the person feels the item is worthy of more than a gamming piece.
When this has happened in the past I have taken the time to congratulate the winner, in an email. Explain to them the value of the item, and have even stooped to the level of offering them a playable version along with the amount of my last bid if they are interested.
Twice now I have been rewarded with an offer to trade some of my lesser valued items for a more valuable item. Thought I would add this to it for those of you who have not done this but maybe thought of it.