(The quoted 5 to brown + 5 to caramelize in TFA is bullshit, though, no question, but most of the quotes in the article aren’t about caramelizing, they are about browning – often lightly browning – in a fairly reasonable time for the level of browning described.)
I’ve read that the lack of sulfur compounds has that effect, and my subjective impression is consistent with that, but I haven’t done structured trials. (And I don’t prefer sweet onions in those applications, in any case.)
This makes a lot of sense and goes a long way to explain the time discrepancies. It's sad that I had to scroll down the page and find these comments buried at the bottom when they should be at the top.
Thin cuts, a decent pan, avoid sweet onions (which take longer to brown), and use a little higher heat than the center of the medium-high range, IME.
Browning is much quicker than caramelizing (see, e.g., https://marxfood.com/caramelizing-onions-vs-browning-onions/ which gives 15 minutes for browning, and an hour for caramelizing; you can push browning more easily.)
(The quoted 5 to brown + 5 to caramelize in TFA is bullshit, though, no question, but most of the quotes in the article aren’t about caramelizing, they are about browning – often lightly browning – in a fairly reasonable time for the level of browning described.)