It's quite easy actually if you understand the nature of transfers, at least i find it "easy".
Players i really want to get rid of, i put on transfer list and mark squad status as "not needed by the club". The last action always seem to trigger interest.
When/If you then get the Wnt icon by your player, use the Offer to clubs option. Of course, you have to set a significant lower asking price than the player's value.
You can't expect to get the AI bidding over player value for players it clearly understand you want to get rid of, it's using that against you.
I personally never had the problem of not getting bids much over the value for my star players. (not transfer listed)
Basically, when transfer listing a player, you tell the AI that you want to sell him, at all costs. Its like an auction, if you know the auctioneer really need to sell the item, you wont bid higly in your first bid. In a way you're asking the AI to take over your "problem" and then paying a lot for it!
I totally understand that your main concern was the large amount of players who never gets any interest. The logic here must be that other clubs don't want a player wich not even is good enough/too old/to expensive/underperforming for your club.
Hope that you maybe got a little more insight on the matter?
Sorry my english, i'm a norwegian