They also seemed to basically do it for two weeks and then stop because the rats "aged out" - despite it supposedly working well and achieving concrete results.

I know rats aren't long-lived, but I would be interested to know how they determined the rats 'aged out'.

Could also be a complete failure they spent considerable effort in with zero results, and are hand waving and constructing a way to quit while claiming success.

I could see the rats not really connecting things and just puttering around. It's a pretty involved setup and I poor uptake on the part of the rats would be a steep disappointment.