Now it is. The legal profession is positively obsessed with Death. This is why economic activities are relegated to separate legal entities. Economic theories, on the other hand, generally assume that humans are immortal and that their economic activities and legal entities which embody them have an infinite horizon. To some extent, this is justified by people's behaviour and by observing the social institutions that they form.
People engage in very long term activities even when they are very old.
No 80-year old inventor will give up his royalties just because he long surpassed his life expectancy and is about to die imminently. This is true even if he has no off-springs. No businessman will stop accumulating wealth just because he has enough for two lifetimes. No consumer will cease consuming simply because he has all that he needs to properly function. The life expectancy horizon is ineffective because w all deny the prospect of death.