I think age is no limit to gaming and to be honest, the generation that "just play bowls" do so in the same way we play video games now. Its something they liked doing in the past or wanted to try out. Its not an age thing, its a time to do it, thing.
I turned 41 in August and when I was 8 I was playing Adventure on the Atari VCS, then progressing onto the VIC20, ZX Spectrum, C64, Amiga, PC Gaming, Playstation and here I am 33 years later playing Mass Effect, Rez, Black Mesa and eagerly awaiting my next paycheck so I can pick up Rocksmith.
Do I have any intention of stopping? Not at all!
I think time I get to play games has decreased due to more demands on my time (family, work etc) but when I do get time to play its solid blocks of time. And just like the old people of today, mooching about playing cricket, bowls and any other old person stereotype game you care to think of, I think come retirement I will indulge in my love of games even further!
I might not have the reactions of a teenager, when it comes to playing Battlefield in 2033 but then again, just as I don't play old school shoot'em ups any more (though FWIW I used to love Xenon 2: Megablast on the Amiga and Ikaruga on the Gamecube) I'm sure my tastes will mature too.
I find myself more interested in story driven RPGs, strategy games and RTS games than I was previously. But that's just natural I think. So in the end I think that this up and coming generation of old people and retired will be the first proper generation of "grey gamers" and come the day that happens to me, I'll be right there along side them!