Could be, could be!
No, it's because of the time of day and the time of year.
The Tube carries tourists in central London pretty much all year round and round the clock. But less in January and very much less the further you come out and therefore the emptier the Tube gets.
I know, I lived between Walthamstow (Victoria line) and Leyton (Central line) for years. And worked in North Acton - the other end of the Central line.
Cherry gets to sit down. Train fills up. Repeat as necessary.
Train empties out. See previous.
Cherry gets out and everyone else getting out is going to the same place.
Same in reverse except everyone else has already left the train and isn't coming to my house.
Elephant and Castle is the terminus of the Bakerloo line South.
And we were heading South at about 11.00, and coming back at about 15.00. Not working hours.
ETA we were moving very slowly because of Dads.
In the Tube photo, we were first on the train simply because everyone else had jumped on the previous one. He had one of his "turns" at the top of the stairs. We were not going to rush. And being the terminus, we ended up with about six minutes to spare before we departed. Hence my posing.
And in the escalator photo we were behind everyone else coming off the train. Same reason.