Except that once your inbound takes off and they know you won't land 45+ minutes before the connecting flight is schdeuled to depart, there is also a good chance that your now available seat may have been given to someone else in need. And that would all have to happen at the latest by the time the connecting flight closes 60 mins before departure, well before you land. There are also other operational issues like checked baggage to consider in setting the cut off (even if you were HBO this time), with extra work, problems and costs whichever of passenger or bag doesn't make it.

I'm not suggesting it's not frustrating, of course it is. But it is one of the obvious risks of booking very tight connections on or close to the MCT on any airline and at any airport. Airlines have no way of knowing whether any individual name on the passenger manifest is a runner or a dawdler so they have to set a uniform cut off that gives them (and us) some certainty.