The authors do mention that. It was written by three professors of evolution and anthropology at Yale, Oxford, and Uni Chicago, but the first comment here is dismissive snark.
>We propose that the regular exploitation of large-animal resources—the “human predatory pattern”—began with an emphasis on percussion-based scavenging of inside-bone nutrients, independent of the emergence of flaked stone tool use. This leads to a series of empirical test implications that differ from previous “meat-eating” origins scenarios.
There's a tendency to think that human intelligence arose because of a series of serendipitous adaptations that permitted intelligence to blossom--eating marrow, eating meat, having opposable thumbs, bipedalism, complex vocalizations, etc. But every time a researcher tries to differentiate humans along an axis, we later discover that these adaptations are actually quite pervasive.
Tool use, communication, calorie sources, etc... whatever early humans did we eventually find to actually be quite pervasive in the sense of independently arising. Which suggests that none of these alone is any sort of bottleneck to intelligence. And if such adaptations are incrementally available then why is it human intelligence exploded so? What's the bottleneck? The only response, again, is some sort of cosmic serendipity along the whole chain, but that's conclusory without any evidence (i.e. showing the bottleneck that prevents all these other species from continuing down the same path and, most importantly, why humans are uniquely capable of squeezing through these bottlenecks time and again).
The scholarship in the article is interesting and useful, but as it regards intelligence it doesn't even begin to answer the critical questions.
Natural selection tells us the process typically works in the reverse order: environmental pressures create a situation where the emergence of increased intelligence grants the individual an ability to leverage the calorie source to their distinct reproductive advantage; not just relative to lions but relative to those in their group. So the marginally improved intelligence mutation occurs first, and it has to be so advantageous that it can overcome counterveiling selective pressures such as more aggressive individuals simply taking the calorie rich source. Were it otherwise we'd be living in Planet of the Apes, or more likely would never have existed.
Whatever evolutionary strategy our ancestors found themselves pursuing, it almost certainly must have been unique and special. The notion that we developed intelligence because intelligence intrinsically provides a reproductive advantage doesn't make any more sense than the notion that we developed intelligence because we could eat fat. Such simple strategies are immediately, incrementally, and perpetually available to countless species, now, then, and prior. If it were true it would imply that evolution is a simple escalator for traits like intelligence, but we see no such evidence of that.