Here’s figure 3, the key chart in that paper:
The most impressive part of the curve is its tails. The middle is a bit of a mess into which all sorts of different curves could fit, but the initial downward slope and final near-horizontal tail really do fit well. There even seems to be symmetry in that the two tails both have just a few data points rather than the cluster of points in the middle. But really, there shouldn’t be symmetry here. The few points in the downward slope are because there is one data point per generation, and the first couple numbers drop by several hundreds. The few points in the horizontal tail are because after Joshua, the only data points included are David and the average Roman lifespan. These are not the only data points in the Bible (the Roman lifespan isn’t even from the Bible), but are simply cherry-picked numbers to make an impressive curve.
Examples of cherry-picking:
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Including multiple people in the same generation. For instance, adding Ishmael balances out Isaac (the curve is roughly between their two ages), and adding Levi – who almost touches the curve – offsets the way Joseph is significantly below the curve.
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Including exceptions while excluding the rule. For instance, they include Joshua’s age of 110 as the sole representative of his generation, even though, as @Boscopup mentioned, the biblical text states that a couple million other people in his generation died before age 60! Suffice it to say that this data would not fit the curve.
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Excluding biblical figures whose age is given, such as Eli, Job and the other kings after David (many of whom did not die violently).
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Creating the tail they desired by including the average Roman lifespan as the last data point, even though it doesn’t come from the Bible and is only one of many figures that could be added.
That would only be the case if God killed Enoch at 365. While some do read the text that way, it’s more common to see something else going on that cannot be strictly equated with death (after all, the genealogy deviates from its pattern to avoid saying that he died). If it’s something else, then it doesn’t follow that Enoch was short-changed.