The second link seems to prove my point anyway, to an extent (as it only addresses 30-somethings and not people in their 40s or older):
As far as men go, once a guy gets to be in his thirties, he’s simply not the machine he once was. His erections are less, shall we say, erect, they are fewer than they might once have been, and his repeat performances are not what they once were. But, as with a woman in her thirties, this doesn’t mean a man doesn’t enjoy sex all the same. He just might have a hard time keeping pace with his girlfriend of the same age, who, after years of practice, has finally figured out what all the fuss is about.
However, anecdotally, in the last few years of my marriage, my sex drive was so high (late 40s, early 50s) my ex and I were having sex daily. Just before we broke up, one day we had so much sex, he came 5 times in 24 hours, a new record for him in 30 years. Age 55! He was having such a banquet of sex, when our kids got older and my fertility decreased, bringing my testosterone forward and increasing my desire.
Also, this article talks of "sex hormones," without defining which ones she is talking about. I mentioned the role of testosterone in women's
sex drive, not just her estrogen/progesterone firings. When there is talk of women sexually peaking around 35, that leaves out all the horny babes in peri-menopause and beyond. Once periods stop, you do away with pregnancy risk, and monthly varying desire, PMS, bloating, bleeding, and cramps. Makes a big difference in one's desire for sex, at least in my case.