Today's evidence: Wilford Brimley.
Now, an actor who perennially looked like America's grandfather is certainly an unlikely player in a genre which clearly favors the young; but Brimley managed to have a very respectable presence despite the wisdom of his years. This is probably owed to the fact that the actor maintained a certain gravitas throughout the years, appearing in roles as a voice of authority, and that inevitably found him being cast in similar roles well within properties folks 'round these parts are familiar with.
Granted, everyone knows him as the aging senior who finds the veritable 'Fountain Of Youth' that was near-and-dear to the SciFi/Comedy Cocoon (1985) and its -- ahem -- inferior -- sequel Cocoon: The Return (1988) ... but he also established himself within SciFi a few years earlier with a top role in John Carpenter's The Thing (1982). And lest we forget his Star Wars connection? I know many in fandom who've long ago dismissed the Ewoks telefilms as inconsequential and even non-canonical, but I remember them with some passing fondness for showing audiences that space Fantasy had a place on network television. Brimley's work as an aging space prospector was good for its era, and I'd be a fool if I failed to mention it here.
Brimley's resume may not be as vast and reverential as others who've come this way; still, I'm doing my part to note his passing and encouraging others to consider his genre contributions in the years ahead. Maybe you can't teach an old dog new tricks, but I for one am glad he dabbled in our realm with every chance he was afforded.
May he rest in peace ...