It is unsustainable in its current form. Of course you can cut benefits, raise taxes, raise age, etc to extend it for however long it makes sense. But it was designed for an evergrowing number of taxpayers, who'd support those before them due to strength in numbers. But as the tax burden grows, more and more people are going to be against it. I don't expect the majority of Gen Z will ever see a penny of it. I'm not sure I will, either.