Secondly - working can be a net benefit to one's health regardless of age. However, it should stem from choice, not need. I wish we cared more for the elderly
Can't say I agree that this is a good idea on the micro level (I have one asian parent and one non-asian parent, currently live in the USA, and do in fact financially support my parents), which is what I think you are advocating. I do agree on the macro level.
On the macro side: there needs to be a stronger belief in the interdependency on all ages on the others. E.g. older, and childless couples should be willing to pay school taxes (those kids will grow up and be your doctors, etc) and younger folks should be more understanding that they will need support wen they are older. There's more of a pervasive "I've got mine jack" mentality here which I think is socially corrosive, and of which the agism is simply an example. When your starting position is that a human's value comes from a homo economicus metric, old people end up judged as parasites.
On the micro side, you can have bad parents, bad kids, childless couples, and manipulation, guilt, etc, so the system isn't reliable. Unconditionality is also known in the west, and abandoning it has been a boon: on the "western" side of my family, in my grandparent's generation, the youngest daughter was not allowed to marry as her duty was to look after her parents when they became old. I consider this inhumane.
For example, I would like to support the smart and diligent kids that could be my doctors one day. However, the straightforward approach "tax adults, support schools, duh" also supports many things I disagree with. First, with more money flowing to schools, schools simply get more expensive, without necessarily increasing quality. Second, it makes no difference between useful education, e.g. the doctors, and useless education, such as... uhm, maybe it is better to avoid specific examples, but you probably can imagine a few.
Similarly, not all "old people" are the same. I'd rather support a former doctor than a former criminal, for example.
On the opposite side, the cultural norm of children supporting their parents also has its problems. Some people may be completely irresponsible, have dozen kids, abuse them, and then feel entitled to their support. Other people may contribute a lot to the society, but they happen to be infertile, or their kids happen to die in an accident.
> Similarly, not all "old people" are the same. I'd rather support a former doctor than a former criminal, for example.
That's precisely the problem to be avoided by universal support. Some people want to make sure artists are supported, some people want to make sure doctors are, some people don't want their money "wasted" on scientists who don't believe in the {insert religious book here}, etc.
> And a higher-level problem is...how to make it politically acceptable.
The US social security system is a good example of this: it was made universal (not means tested) and mocked up to look like an insurance program with the explicit aim of making people believe that they "paid into an insurance system so are just getting their money out". Of course it's not really like an insurance scheme at all, no more and no less than using your current taxes to build a bridge that will be used for years.
It's quite interesting to read the contemporary (1930s) internal discussions to see how nakedly they propagandized the description of the system to make sure it wasn't later killed. It's a great system; shame they had to prey upon widespread economic ignorance to manage to put it into place.
Philosophically I personally dont see why the obligation should be on the children to support the parents. The parents choose to have children not the other way around.
I love my parents but do not feel any requirement by them to care for them. They have saved for retirement just as I am. If people choose to not save then their poverty in their older years is a problem they brought upon themselves.