Yes, but if we agree that price undercutting is worthwhile on many (though not all) items are we looking at undercutting the average price which is fair and realistic but may be like trying to sell a Christmas Tree in a Fir forest or do we undercut the lowest price which is flat-spin-economics and actually often impossible margin-wise unless you're one of those who like paying folk to take your stuff away (they do exist). Therefore, it seems reasonable that those of us wishing to get a fair price should be aiming at using our fees advantage to slightly undercut the average price and hope that it's enough to get us noticed.
Re your examples, speculative pricing is OK - it's all fishing - you can cast worms in a pond you know is full of roach or you can spin for a big pike that may not even be there - it's all fine.