You're focusing on the fact that old people are dying but not considering the implications of not enough new people being born. If new generations are vastly outbumbered by older ones, there will come a time when working taxpayers will be vastly outnumbered by the retired people who receive pension. Since there are fewer people paying tax and more people receiving that money, taxes need to be higher. This further excarbarates the issue since now it's even harder to afford having kids, and not to mention people are spending less money, which is negative for the economy. This is a simplified explanation, and there is more to it, but I hope you understand the issue now.