There are also probably very personal and biological variables involved too that the post doesn't mention. I stare into monitors and phones all day long. Every light in the house is full-blown LED. I can't help but fall asleep at 20:00 in an led lit room watching led TVs, while my led phone drops onto the floor after I've fallen asleep. I've been in an extreme LED environment for over a decade and never have problems…
I can confidently say you're so right about the number (and type) of variables. Sleep hygiene as we say in the biz is a very complex and personal issue.
I've tried everything under the sun from strict routine, screen avoidance, both abstinence from and ample sex, more reading, less reading, zero caffeine, limited caffeine, ALL THE CAFFEINE, changes to diet, fasting, supplements, and even medication.
There are usually relatively minor, short lived improvements but it's only a matter of time before I'm spending my nights once again staring at the ceiling, mind at full-tilt.
Whenever sleep comes up in conversation, and I mention my struggles, I feel like invariably I'm met with a response along the lines of "you _just_ have to...", and "have you ever tried ...?" followed by some arbitrary rule or herbal remedy.
Since about the the introduction of the first iPad, consensus seems to have formed the root of all sleep evil is screentime.
Sleep (for some) is an incredibly sensitive and personal struggle. Alarmist "mankind is doomed!" make it even harder to understand the greater picture.
It's closely related to diet. There's always some fad trending, and a number of people who find success in choosing a "better" diet almost always have a system they'll fervently claim is The Way.
The science is relatively clear on light though. I just appear to be some form of mutant.