I don't think it's ageism. It's a good observation.
Unfortunately, as you progress up the ladder in the industry, you're more likely to be attending conferences in a management capacity. I know this as I'm right there now.
The younger people here are doing, not attending conferences.
"..the smell of death" isn't ageism??? I happen to agree that any good conference's should represent a cross-section of that industry. But the fact is that software development in particular tends to discard older professionals as not valuable.
Newsflash: Younger people get older too and still enjoy coding for fun and profits. And many of them are just like younger people, trapped in aging bodies.
Just because you're not seeing younger people at agile related events, doesn't mean they're not using agile methods where they are 'doing' stuff.
Unfortunately, as you progress up the ladder in the industry, you're more likely to be attending conferences in a management capacity. I know this as I'm right there now.
The younger people here are doing, not attending conferences.