It's just there's some actors who are still like, "big" even into old age, for a major "off the top of my head" example, like John Wayne. From what I've read Wayne was still making good grossing films until he died. I always saw Harrison as sort of our era's John Wayne or Bogart, as in, always saw him in that same sort of "old fashioned leading man" vein.
I've been a critic of Ford's acting but on reflection it's more the roles he picks than his actual talent. Ford came up during the era where all the big stars (Pacino, DeNiro, Hackman, Brando, etc) were intense method actors, and Ford was like a refreshing throwback to simpler times.
Of course, all stars must fade eventually, I suppose, but I am a fan of Ford and do wish he was still big like he was in the '90s. I remember when I was a kid, if there was a "King of Hollywood", Harrison was it, IMO. He personified the "man's man" for me growing up. I even love a film of his most hate--Six Days Seven Nights. I just wish, even if he can't be a big star again, that he'd pick better material. He had a string of winners for over 20 years.