Out of anyone, I have always said the bike is the least important element of success on a long brevet. I am sure the Rohloff would be fine, just not my cup of tea.
I rarely even look at fellow randonneur's equipment because the most important equipment is invisible, the six inches between one's ears.
This was a long thread with many off topic posts once the OP's question was given a thorough perspective from many different randonneurs, all valid points and merely just opinions. I do not even remember all the different discussions but IIRC, there was never a concern with the Rohloff hub failing. The main considerations were gear ratio spacing, ergonomics of the shifter, lower efficiency, and if the rear wheel pretzeled, it is probably DNF.
To be able to enjoy something like PBP, being as fit as possible and having an efficient bike certainly helps the average cyclist. I would not consider someone like Sophie to be average, she could probably ride anything and finish. A friend of mine ran out of time and it was really just an hour or two. If he just did not have Gatorskins on and if his jacket wasn't so floppy, he could have finished instead of being outside the limit. It haunts him.