in all reality, these games would never die, and expecially the heart gold, and SS.
and coming from the old timer, i i remember when gold and silver originally came out (remind you, if you ask any old timer 80% of them will tell you that Gen 1 and 2 we're the greatest out of the games). and these games we're just unimaginable to their extent.
So when red and blue originally came out, these we're the most unique games of it's time.. For playstation you had Final Fantasy 7 and Xenogears.. for game boy, you had pokemon or pacman or bomberman. and pokemon clearly hit the charts destroying everything in it's path. a Unique RPG where you can see your pokemon level up and take them through a journey of a game that takes forever to beat? it was un-herd of for it's time.
When silver and gold hit the market, whole new beginning (with the best pokemon class IMO) and it was amazing, alot more free-space, bigger map, new adventure, new hms tms etc you name it was there. When you got done with the game, game is usually over right? No.. they re-introduced red and blue BACK into the story mode with silver and gold.. there is just no comparsion to it and i wish they would do this with the newer pokemon games as well.
So all in all to your question, these games will never die. EVER.