Since the OP's question is specifically about collecting over an extended amount of time. For folks 50+ years old (having grown up during the heyday of slipjoint collecting) that feel as if they qualify as a collector: What traditional slipjoint brands did you collect prior to 2000? Mine were Winchester, Remington, Cattaraugus, Schrade, Camillus, Fight'n Rooster, German Bulldog, Eye Brand, Henckels, Kissing Crane, Boker, Hen & Rooster, Queen (including Schatt & Morgan, Mooremaker, Winchester reproductions, and Case Classics), and Case. I'm sure I have forgotten something - but these were off the top of my head.
Now, same folks, what current production traditional slipjoint knives are you collecting?