Comparing the ageing process and how well someone, anyone has aged in the comparative nature of ageing, when placing a man in his 50's with a man in his 70's is pure nonsense I'm afraid. The 20+ years between a man of Smith's younger self and his 'self' now, with Ford's aging in the same interim years (50's to 70's) is always going to be pointless, one ages more and increasingly 'downhill' in the time between one's 50's to 70's than anytime in one's lifetime, that 20 years, particularly if you've had a 'tougher' life, make for some damaging aging, rather than 30's to 50's where it's not as bad.
For example, I'm in better 'nick' in my mid 40's than I was in mid to late 20's, but once you hit 50, where your body is, at whatever state that is, is pretty much were your body will be going into your 60's and 70's. The body breaks down basically and is in 'free-fall' beyond 40.