So I don't think this is something historically people have believed in youth and rejected in adulthood. It's only coming to a head now. Of course, it's reasonable to expect that the current entrants to the scheme will continue to try to perpetuate it once they've committed significant resources to it, despite complaining loudly about the scheme now, not least because many will have little choice (they will be in a worse place than prior entrants, having had to commit proportionally more resources prior to drawing their benefits, and generally be expected to receive fewer benefits when they do, as the schemes adapt to the situation).
What this rhetoric really boils down to, AFAICT, is trying to push some of that burden back up the pyramid earlier, so that the bust is perhaps shared a little more evenly. i.e. by reducing the benefits of current recipients so that they are more inline with what future recipients can be expected to receive. I suspect it is a fools errand, though, since these are typically legal obligations, so would need very controversial legislation to enact. I can't see "stealing from grannies" ever passing a democratic legislature.