Because of a mouse, a mouse that lived for five thousand days.
Money was the last thing to go. It's so peaceful now. Many utopian visionaries thought it might be the first. They were strange days during the global warming reverse. Money was tight, but people lived meeker and happier than before.
The first of them were ecstatic and playful, but as their numbers grew and the realisation dawned on them, their fear increased and the petitioning turned fierce. The old ones started making a big noise. The older they were, the more they cared. The first immortals were our saviours; never had we before cared so much about the future.
The medical trials that had first given middle aged people a spring in their step had progressed to the point that grandparents were rejuvenating, winding back the clock. The gift of a fresh chance at living some more was rejected by many of the elderly, but the ones that took it, drank it up and showed the world how wonderful it could be.
How wonderful until the immortals realised that they were destined to live in the world they had left to their children's children.
There was one tv interview between one of the immortals, looking no older than thirty but actually about seventy, and the president. The oddity of hearing the language used, old slang and calling this apparently more mature man "son" didn't grow old until there were more of them than there were mortals.
The green movement swung full force and toppled all talks of economy and war.
The world, so interested in this topic, calmed as it worked hard to change the direction of the damage. Reduce and reverse the warming. As more and more immortals were created, more and more educated people were available to educate and help out. Over a period of only ten years, we had gone from a ten percent geriatric society to a virtually ninety percent working age. The difference was most apparent in how well the universities were doing, more incomes meant more taxes meant the grants came back for students, and suddenly, the care-worker jobs taken by many students were gone, along with the need to have jobs. Junior nurses less required as there were less ill people in hospitals. The world was healthier. Humanity was healthier too.
And all this because a group found a combination of drugs that would help a mouse last for five thousand days.