This is false, in my opinion. According to studies, the average length of intercourse from reading is anywhere from 3-14 minutes. Since different studies provide different results, let's split the difference and say the average length of sex is around 8 minutes.
For a great deal of people, that might be way longer than they're used to lasting, for most it's probably in the ballpark, then you have the other outliers, the men who can last well beyond that.
Just including intercourse, if I last 15 minutes I consider that quick for me. On average I'd say I last around 25 minutes or so, with my longest sessions reaching 45 minutes to an hour, and this is AFTER any foreplay.
So it is of my opinion that bedroom game is NOT simple. If a girl is used to the average guy and having sex for 10 minutes or so, then if I come in and blast her for 30 minutes, she'll be overcome with pleasure and attachment as she is blown away by the best sex she's ever had. The more experienced she is, the more likely she is to keep coming back for more because she now believes it's unlikely that she'll find someone as good.
One girl I dated was a virgin, and she hasn't been with anyone since me, but while we were together she always talked about how even though I was her first I effectively ruined sex for her because it will be very difficult to find someone of my size who can go for as long as I can. The girl I'm currently with has been with 3 people before me, and constantly tells me how amazing I am after going at it for 35 minutes and making her have what she claims to be "a constant never-ending orgasm."
So I agree it's not rocket science, but some men are blessed with more stamina, bigger size, etc, and others work hard to achieve such abilities. They tend to pay off in my opinion compared to the average man.