> It's easier just to declare a retirement age.

I think that's a fair argument. But 65 is probably way too young as a threshold in this day and age. I happen to know a lot of 65-ish Americans, because that's right around my parents' age. And the vast majority of them are still capable of working.

Which isn't to say that they're not enjoying retirement. But they most certainly don't need to be retired. I'm happy for them if they can support themselves. But I don't think public finances need to subsidize healthy people's cross-country RV trips.