Re: "It's not remotely possible...
"It's not remotely possible...
"...to provide any product "for life" that has recurring costs associated with it."
Of course it is. The lack of recurring revenue doesn't by itself make the model unsustainable. Somebody's already mentioned the annuity business which relies on accurately forecasting how long "for life" means on average. The other method simply depends on the average churn rate as people naturally move on to something else.
For example, I have a lifetime membership with sdf.lonestar.org for remote access - I use it as my primary news and email account, a stepping stone in various remote access cases (behind firewalls etc), and as a dumping ground for various small bits and pieces I need to access from anywhere. It cost something like £15 twenty years ago. I've had far more value than that since.
It's a non-profit with public accounts, though, and you can see that it is not in financial difficulty of any kind, even though the lifetime accounts make up the largest share of revenue. The majority of users play with it for six months or so and then move on to something else. Since it's a "lifetime" membership people don't feel the need to use it to get their money's worth and many simply never return after a while. Overall, the model is perfectly sustainable, even if some people like me are effectively subsidised by the short-term users.