Das hat nichts mit "zutrauen" tun, es geht auch nicht um den Zutritt von Tieren.
Deshalb ist es sinnvoll, bei Interesse die Studie zu lesen.
"Flowstone formation continues today (Flowstone 3), changing the morphology of cave passages. This makes it possible that a more direct access-way or easier passage may have existed when hominins entered. A different entrance into the chamber may also explain the presence of rodent bone concentrations in Facies 1b. However, sedimentation patterns indicate that the accumulation of Unit 2 with fossils occurred below the current entry point into the chamber, and alternate routes did not involve vertical access shafts that connected directly to surface in either the Dinaledi Chamber or nearby Dragon’s Back Chamber. The lack of other contemporaneous fauna in the assemblage, and complete lack of surface modifications by vertebrates (carnivores, scavengers or rodents) further suggests that the Dinaledi Chamber remained undisturbed by other animals, which could not reach the chamber. Taken together, this means H. naledi would have had to traverse difficult terrain to reach the Dinaledi Chamber, with the chamber and the proximal entrance to the chamber positioned in the dark zone."
Die bislang betriebene "exhaustive search" hat jedenfalls zu dem bislang "only identified access" geführt. Ausdrücklich ausgeschlossen werden morphologische Veränderungen nicht, siehe oben. Wäre auch geologisch Unfug über solche Zeiträume.