Perfectly cast in one of the funniest movies of the 60s.

You could be right, but people also want to remember them as they were in their prime. Its denial!
Norman! What did you put in my tea?

I take it more that they are shocked to not see them look as they used to in their younger years and are not used to it.
But they should be because that happens.

Some people age more gracefully than others, but seeing someone old, when they are old too, can make them feel a little insecure and its just a projection. It may even make them feel better about themselves too.
Norman! What did you put in my tea?

Thank you.
Yes.
Another one I don't get that I am hearing as the baby boomer gen. is entering their senior years is when they see a fellow baby boomer celeb:
"(Insert name of movie actor) is really looking old!"
Well, duh!
People age!

They still exist on discs and digital.
You can watch them anytime you or anyone else wants to.
I never got why peeps feel that its sad when celebrities, or even any person they don't know personally, pass away which is just a fact of life for EVERYONE. Yes, a death can naturally and even understandably be perceived as tragic, but it aint' a new phenomena and one that has to be lived with.
Its a strange entitlement that they want them to still be alive for some distorted reason which makes no rational sense. Like you say, they are immortalized on film.
Norman! What did you put in my tea?

Stupid OP bitch.
They still exist on discs and digital.
You can watch them anytime you or anyone else wants to.

Indeed they are perfection.

they make a great duo alright, but i've seen better movies from them
so many movies, so little time

Yup, they were great together.
Esta es mi firma

Can't agree about your assessment about Matthau; the role was tailor-made for him. His acting was superb and I can't even imagine anyone else as that sportswriter.

Jack Lemmon was good, but Walter Matthau was hideous

Heck yeah,I like both of them,toothese dudes just about killed it in everything they didtwo true classic old-school actors doing what they did best, whenever they teamed upthey really made this flick work.