I knew someone would say this! That is why I gave example of Avatar. Do you know? Rajesh Khanna's looks were on a steady decline those days! Receding hairline, increasing paunch and face laden with acne and wrinkles. Smita Patil was also never considered a conventionally beautiful woman. Both of them were further made to look old grandpa-grandma types in that film with silly white streaks in their hair and a hideous wig on Kaka's head.
Yet both of them complemented each other so well!
Mind you! They were not playing a married couple in it. It was not even like a love story. It was just about two oldies connecting on common ground of neglect by kids of ageing parents. Still they looked like a couple in it and gelled well.
Why shouldn't actors be compared? The old films were made years ago and with less budget than budget that today's top soaps like BV enjoy!