Letting OAS erode relative to wages (compared to a history of ad hoc increases despite the formal indexing) doesn’t fix the fairness issue, even if it fixes the budget issue. This is still young people paying most to solve the problem, contributing just as much of their income now for a less generous benefit later. (In fact, the only real appeal of pay as you go programs is that if wage growth is high benefits that keep up with wages may very well beat private saving, at least in lower-risk investments).

You might hope wage growth would be reasonable compensation to today’s young, but so many big costs (say housing, or labour-intensive services) are about what you make relative to other people. This is half the reason the ad hoc increases to benefits exist in the first place. You can only grow your way out of the entitlement problem if we’re willing to let seniors lose ground relative to young people (which has absolute consequences in some aspects of standard of living). Particularly for GIS, it’s hard to see a world in which wages double and the floor for seniors stays the same.