Just spotted your post Kane. One thing the automotive industry taught me... when a soft item is in constant contact with a slightly harder surface, say for example, spotlight wires rubbing on the much harder plastic car grille.. contrary to what you may expect... the harder surface will wear out first. Reason: The softer plastic coating on the wire will move, lessening the wear factor thereby causing more wear to be evident on the hard plastic of the grille.That's why you'll see those marks on your truck's grille where the wires sit and rub.
Applying the same principle to your hard graphite surface and the soft top ring you can then see where the abrasion will be the greatest. Salt crystals are very sharp and abrasive... like tiny cutting compound.Just the movement of the rod during the normal course of one day's fishing will have dust or salt particles chafing away invisibly. We're better off pulling biketube over the rod butts and leaving the holder alone..Why protect our $25 rodholder and not our $500 rod..?
So mate, the rodholder manufacturers didn't get it wrong... it's just that the rod builders haven't got it right yet!
Marketing opportunity for some clever fella here...? Nah! Just apply the bike tube!