This is true. One player I got from Negotiation stayed there, even after unsuccessful bids were placed, because he was never skilled up further. I was able to sign the player a couple of days later with an increased bid.
I'm pretty sure that players also go on Negotiation if a direct bid has been placed on him by another owner. At that point, you'll be able to bid on them, too.
EDIT: There's actually such a player on my Negotiation list at level 14. Bernardo Silva, a 22 year old 4* CM has a total rating of 254.6, leaving him two skill points shy of going to Scout for the bidding owner, who's on level 13.