Paleolithic people did not all die before 30. The AVERAGE lifespan was about 30, but the main factor in bringing it down that low was high childhood mortality. Obviously there was no modern-day medical care in the Paleolithic, so a fairly high percentage of people didn't make it to adulthood due to injury or illness. If you survived the usual childhood mishaps and diseases, you had an excellent chance of living to a ripe old age, almost certainly in better health than many folks of comparable age today.
Honestly, this misconception about life expectancy is so widespread it is hard for me to believe so many people don't understand the mathematics of averages. An AVERAGE life span of 30 does not in any way indicate that 30 is the maximum age attainable, or that 30 is "old", or even that most people died at the age of 30. AVERAGES, people!!!!
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Always been a pet peeve of mine...