I think every study like this should be looked at and considered as a work in progress and as information that doesn't exist in a vacuum. Also, quotes like "This matches some anthropological estimates for early modern humans." might be ones to consider, as other sources do agree that a lifespan in the 30s was at one point to be expected, but it began extending past that 30, 000 years ago. So when the original study talks about 30 as the upper end, is it looking at an age where an early hunter-gatherer type human would be unable to keep sustaining themselves with that lifestyle? Is it because they are no longer fit enough to keep hunting or is it because even if somebody else fed them that all the other circumstances would just pile on? Is the idea of DNA estimating lifespan also looking at the idea that once an organism ages to a certain point and slows down it statistically dies from predation as well? Since that is something humans as a whole have been able to get past with intelligence. I don't know exactly how that all interacts, which is why looking at a lot of data is important before declaring something.

Which also brings up the idea of an average in relation to an expected lifespan. It is a commonly known tidbit that while the average lifespan in ancient and medieval times would usually be estimated somewhere in the 30s (depending on the exact era, location, and methodology), that's an average dragged way down by infant mortality, and that people who made it out of childhood would have higher expected lifespans. I bring this up because looking at the OP linked study and then skimming a look at average lifespans might make the idea of DNA-destined-dead-by-30 a lock, when it really isn't.

Obvious advancing medicine increases the population average lifespan. A human 30,000 years ago born with diabetes probably wouldn't make it very long while one born these days with proper medication lives much longer. Does seeing the population average lifespan number go up have any relation to another individual, specific human who doesn't have any sort of chronic illness? No, so again just looking at raw population averages as just one way of looking at expected lifespan is something to keep in mind.

The conclusion is that it's an interesting study to keep as a link, and use as one piece of data if you're really interested in gathering more information.