Nostalgia! Oh yeah, that's a good reason behind continuing gambling too for old people.
I am a nostalgic person. Why? I still prefer playing PSP, and PS1 games despite the fact that there are more better games in consoles in this era. Why? It brings back a lot of memories.
I do think it will have the same effect on old gamblers or those who are getting old. Let's say they have a favorite slot game today and even though they will be creating new ones in maybe the next 5-10 years, he will still keep on going back at that same game and just play around running it with small bets just to have some fun.
That may be why I answered here I will keep on playing or betting even in my old age. But I might prefer 1 or 2 bets only on sports and just cheer for my preferred team while watching the game with my bet on the line.