If a cheap, reliable technique of halting or slowing down the "epigenetic clock" hits the market, and assuming its main effect on a population level is increased life span, wouldn't it make the demographics of most developed countries even worse?

It's still unclear whether or not "automation" will compensate an ageing population, and prevent a demographic collapse. But having a pill that makes people live longer (even if it's 5 to 10 years), wouldn't it be like throwing an entire gas station into the fire?