They could invest like 10billion in curing aging (life extension sciences, generally), so they could enjoy the rest 90 for a lot longer than they'll be able to with a current average lifespan. Actually - all of that money means nothing, as most of these people who control 'em are already in the middle age, and will be 6 foot under the ground like 20-30 years (if they are lucky in the gene department) from now..