So JWittz put out an episode recently about the topic. And while this kind of thread probably has been up in the past, I thought I'd share my thoughts on the topic.

We'll start with his mother's admission.
[...]It took your father three days to reach Viridian city. Oh he'll be so proud.[...]"
By that statement, that means Deliah has contact with Ash's father to that day, and that he's alive.
I have to say though, that Silver (from Pokémon Chronicles) having so many similarities to Ash, and reacting that way to hearing his name leads me to believe that Richie met Mr. Ketchum.

Of course, it could also imply that Silver is Ash. Let's face it, this wouldn't be the first time that Pokémon has pulled the "time shift" trick. Pokémon 4eva ring a bell?
But with this theory, that would imply that Ash DOES age, and that he lost Pikachu somehow, be it death or some other reason.