Very few do. They feel like they're being 'paid back' for the money they lent the government. This is why they feel entitled to their entitlement. And I'm not really making a moral judgement on this, except when they complain about it being unfair and then hypocritically don't acknowledge that that modern taxpayer is paying them back for a debt imposed upon them by someone else. But this doesn't change that SS was started out of sympathy and that it doesn't easily handle an ever-expanding number of retired people living longer. It will need a solution, and 'healthy people continuing to work' shouldn't be outside the list of possible solutions. People who think they're 'owed' a retirement have a reasonable moral claim to the profits of their work (both first-order AND second-order), but then asking for a ever-expanding share of those profits just won't work.