This really has nothing to do with limits to longevity in any practical sense. That's just the publicity machine at work, the first line in mangling and misrepresenting the relevance of research. This paper is to do with a long-running debate over whether or not mortality risk reaches a high, flat plateau in extreme old age. The difference between limit and high flat plateau is academic for those involved. The outcome is much the same.

It does in flies, and there is very clear evidence for that. The evidence in humans to date is very sparse, and where people have done good work on the numbers, they have not seen signs of a plateau. So in that sense, that people have found a larger data set that shows it, that is fuel for the fire.

No-one has the slightest idea as to how you can balance the fundamentals of reliability theory with a late life mortality plateau. If damage is accumulating, and no-one really believes it stops accumulating, then your risk of mortality should keep on going up. What sort of mechanisms in a highly damaged biology could buffer that underlying reality? And why in very late life versus other times?

None of this, of course, has anything to do with efforts to treat aging or extend human life. It is an academic debate that will likely fade out before answers are found, made irrelevant by the advent of ways to treat aging and its causes. Methods of extending life will work by putting off or repairing the very damaged state. There will likely never be a large multiple of the present count of exceptionally physiologically aged individuals. Rejuvenation therapies are just around the corner.