...the implication here, as expressed by your interpretation of Jim's remark, is that the obsolescence of Nevada chips is a function of either their demonetization by the casinos of issue or the closure of the casinos.

Now, some Las Vegas casinos, for example, have never demonetized any of their chips... Caesars comes to mind as one illustration. I do believe that you may still cash in a first issue $100 chip, for example. By your definition, then, these first issue Caesars are NOT obsolete. Is that a definition that you can live with?