Different views on the sustainability of old age security

I'd mentioned before that Old Age Security payments in Canada seem to be somewhat of a ponzi scheme, but that's not the only claim that you'll see made, with a Globe and Mail article arguing that "Expert advice commissioned by the federal government contradicts Stephen Harper’s warnings that Canada can’t afford the looming bill for Old Age Security payments."

A counterpoint to this would be the following argument:

Jack Mintz, director of the School of Public Policy at the University of Calgary, said Tuesday that research he has done for the federal and provincial governments has shown the OAS system is sustainable on its own. However, he said Old Age Security reforms are likely warranted because the system is one of the mounting fiscal pressures faced by the federal government due to a greying society, while OAS changes are likely a lot more palatable than cuts to medical funding and services.

So if OAS seems sustainable on its own , but that to do so would compromise the ability of the healthcare system to keep those same people healthy, isn't that still the same basic sort of problem?

BTW, here's what the system originally looked like:

When OAS was introduced in 1952, retirement eligibility was 70 years of age while the average life expectancy was 68. Many would have passed away before receiving OAS. During the years 1965-69, the eligibility age was moved down to 65, even though life expectancy was increasing. Now, with life expectancy above 80, most Canadians qualify for OAS for a very long time after 65.

It's much easier to run a benefit system when the age at which benefits start to be paid out is higher than average life expectancy. Now that's changed quite a bit, but to pass such a measure also seems to mean that those currently receiving benefits or going to start receiving benefits in the next few years will be unaffected. Intergenerational wealth transfer... it's not just the national debt that that can be done through.