There's multiple issues there:
1) there's spartan explicit connection between the taxes paid then and the pensions paid now: most governments did not put that money in an explicit infrastructure or investment fund, the revenue from which explicitly pays for pensions. Additionally, we generally do not (in Australia) connect how much you paid in with how much your taking out, so we have no way to even ethically or materially judge whether someone really is our isn't "taking out more than they put in"
2) in the real economy, pensions are not paid for by your past taxes, but from future income derived from the level of capital investment and infrastructure and the labor force at the time of your retirement. The Australian pension system contracts a population of post boomer children to pay a debt they were never party to agreeing to pay: and chicken the general demographic numbers, aren't liable to be able to pay it given the relative size of the two populations.
3) from a normative point if view, the Australian system is quite generous (not as generous as some of the European ones). It is, dare I say it, unsustainable. Not only do you have to adjust for the pensioner discounts and additional payments offered to get it's true value, but it is much greater in volume compared to all other dole payments. With no means testing for your primary property, it's both a subsidy to the rich, encourages over investment in property, and has basically set us up to escalate inter generational war fare.
My advice to everyone is to assume it won't be there for anyone not already collecting it.
Don't get me wrong, I have some sympathy for the boomers who thought it would be available. But, they got to effectively overconsume by not putting sufficient away to invest for it, and in a competition between economic reality vs "what I'm supposed to get on my defined benefit pension", reality will win every time. Government isn't god.