No time for retirement

One of the current discussion threads in the RIBA's Linked In Group is about the age at which architects should retire. The consensus is that they can't or shouldn't.
We are used to the grand old men (still mostly men) of architecture whose practices create some of their best work at an age when most other citizens would be putting their feet up or indulging their hobbies. Lords Rogers and Foster are the highest profile examples. And the clue of course lies in the word 'hobbies'. For many architects, nothing could be more interesting than architecture, so why shouldn't they continue doing what they love? Few will manage to emulate Brazilian superstar Oscar Niemeyer, still designing on the wrong side of 100, but many would love to try.
The situation is not all sunny though. None of the contributors to the Linked In discussion are famous and many sound pretty dissatisfied. Several are certainly working because they have to, and have cashed in pensions in order to keep their practices going. Worrying about the best design solutions in your 60s and 70s may be stimulating; worrying about paying the bills is less so.
The other problem is the dilemma facing young architects and would-be architects, struggling to find work in a cruel economic climate. Should older architects retire to make way for them? This is not an easy question. Architects running their own practices can't simply step aside for younger people. And many younger architects are responding to the difficult economic climate by setting up their own practices. The Architects' Journal has been profiling one a week for ages, and the list seems endless. This is a situation where the market really will decide, as clients choose their architect perhaps on the basis of experience, or perhaps on the basis of youthful enthusiasm. Many of the younger practices are expanding the traditional idea of what constitutes architecture, and finding work through new avenues. Perhaps some of the non-retirees should do the same, and develop new 'hobbies'?
One at least has an idea. David Grube, who runs an eponymous practice in Sheffield, suggests that 'Grumpy old  architects' could be a natural successor to 'Grumpy old men'. I wonder if that could work.