That is far from clear. It is even far from clear that this is true all else being equal, and all else is definitely not equal. Extending longevity exacerbates the strain on global resources caused by overpopulation -- most notably at the moment, the capacity of the planet to absorb carbon emissions, but that's a detail. Exponential growth is not sustainable on a finite planet. If carbon weren't the limiting factor, it would be something else.

But we humans were designed to die. Our evolutionary purpose is to raise children to the point where they are able to have children of their own. A longer lifespan than that doesn't advance our reproductive fitness, and so we're not designed to live any longer than that. So even if we could tweak our bodies to live longer, it is not a foregone conclusion that this would be healthy for our minds and souls.