To add an data point:
Had a recent JFK-MAD-AGP connection (one ticket) with 1:20 h scheduled between flights.
JFK-MAD arrived around 20 min late at gate, arrivial gate at T4S was around half down the terminal, luckily no queue at the passport machines, took elevators down and first car of the train (I followed a cabin crew who seemed to be in a rush too), transfer security at T4 decided to send my back pack to secondary (didn't happen anywhere else on that RTW trip) which was done at leisurely pace...
Departure gate was K73, so another 3/4 terminal length away.
I arrived sweating and a bit breathless at the gate where I was one of the last 3 people to board, scowled by both GA and FA for my carry on on wheels ("no more overhead space!!"), only after realizing I was in C they became friendlier again.
Ergo: Not a connection for the faint hearted and not sure how anyone less mobile would have made it, and impossible if it would have been 2 seperate tickets with checked bags.