My recollection is that the last inbound train was basically a repositioning that allowed passengers.Ridership must be terribad. Second shift workers that might have taken the train are probably driving or maybe still WFH.
Take the Worcester Line. Outbound the last train is only 30 minutes earlier. But inbound is nearly two hours (train used to leave Worcester at 12:20 AM). I bet the Inbound trains would be basically empty if they continued to run it.