I guess with something like this, people should do what makes them happiest. In a relationship, this is likely to be a matter for discussion (or at least the partners ought to be open to it being discussed); even with casual sex, it can sometimes be good to find out what the other person thinks about something like this (mostly likely as you go along).
The article makes it clear that by "sexual intercourse" here is meant the time " from penetration of the vagina by the penis until ejaculation". This seems a very "clinical" and rather restricted definition, but on those terms, then yes, I think minutes not hours is right for most people.
In terms of getting my rocks off and release of tension, I can be happy, sort of, with a couple of minutes *any less than that I don't think that I've enjoyed the actual physical sensations of being inside for long enough. But even with completely casual, one-off sex I go for longer than that, partly perhaps through habit but partly because I enjoy it and, I think usually, so does my partner.
In a long-term relationship, the actual "sexual intercourse", as defined by this article, usually melds and melts into the whole experience of "having sex" or "making love". Sometimes the actual "sexual intercourse", from penetration to ejaculation, isn't even one single episode having gone for a while, we might stop that and turn to something else, particularly oral, before going back to in-and-out "sexual intercourse".
That said, I've had some pretty long sessions of uninterrupted fucking ("sexual intercourse"), but I agree that it's not every time. Probably 1015 minutes of actual fucking would be typical, but sometimes it's longer, and sometimes much longer.
Then of course there's the quickie, but that's a different thing.
