I think that there are some factors that favor younger people when it comes to decision making, and some factors that favor older people.
Younger people tend to be more creative and flexible in their thinking. As they get older those tend to diminish, but they gain knowledge and experience. I suspect that until somewhere in middle age the gains from knowledge and experience beat out their thinking becoming less flexible and creative when it comes to making well thought out political decisions.
it's not about decision making, it's about incentives. No one is arguing for a performance based voting algorithm. A young person will eventually have to be an old person, so they must balance the interests of both. An old person will never have to be a young person again though, so they only vote in the interest of themselves.
Because younger people have less life experience than older people?
How many times do you see articles about 18-23 year old people doing something stupid, and people come to their defense saying something along the lines of 'They're only children!'?
You misunderstand. if you are operating only under the assumption that your voting power should be proportional to the time you have left to live, then there's a pretty clear age-power relationship.
If you add an assumption about life experience though, You're going to have to be a lot more specific to explain how these two functions interact. why is the optimum in the middle? Why isn't it bumpy?
As soon as you start adding other factors into your weighting function, I don't know how you can be confident in the shape of your graph without being precise with your functions.
To be fair though, I think that there's a pretty good argument for inverse age weighting. If you're 20, you will eventually have to be 35, so it wouldn't make any sense for you to screw over 35 year olds. If you're 35 though, you'll never be 20 again. There is no incentive for you to not screw over 20 year olds. (unless you have kids, but at that point, everyone has equal investment in society and the premise falls apart).
And on the other hand, old people's poor decisions are often blamed on their age as well. The elderly are prime targets for most scams because they are perceived as more likely to fall for them.
Younger people tend to be more creative and flexible in their thinking. As they get older those tend to diminish, but they gain knowledge and experience. I suspect that until somewhere in middle age the gains from knowledge and experience beat out their thinking becoming less flexible and creative when it comes to making well thought out political decisions.