Retirement

Why haven't anubody, or, any country, suggested the following retirement scheme:
Age 50: 3 day weekend
Age 55: 4 day weekend
Age 60: 5 day weekend
Age 65: 6 day weekend
Age 70: 7 day weekend
I'd say that a lot of people would be a lot happpier if we tried this and I bet it would increase both productivity and employment.