I can understand that a baggage can't make it during a 75 min transit (though quite surprising), but not for a 7 hour transit.

For the anecdote, in November last year, I arrived at the airport (major European outstation) less than 30 min before an inbound flight, due to exceptionally heavy traffic. Boarding had already started when I showed up at check-in. Well, my checked baggage made it onboard. I still don't know how.