In most developed country there is a problem with ageing population. The problem is that old people suck out lots of money from government funds. We have costs of health (e.g. Medicare) as well as pension costs. The problem is made even worse because developed countries tend to have lower fertility levels, which means less people work, which means lower tax revenue. Immigration can easily fix population decline but it is uncertain whether it has much effect on age distribution.
One solution that will defintely work is simple killing of old people. When an old person is, say, fifty, they will be required to die by taking a tablet. This of course would be very unpopular. Even young people may not agree to it because they would dread the thought of having to die once they grow old.
Another solution would be to take away welfare and let those who can't take care of themselves die. Once against this is very cruel and by bringing it up I am only playing devil's advocate. But many people argue that foreign aid should not be given because "we need to take care of ourselves first." So if people within a country can refuse assistance to those outside a country, why can't those who are capable of taking care of themselves refuse assistance to those who can't take care of themselves?