That's a very simplistic view of apnea. You don't have to be fat to experience it, and this misconception is a bit part of why it's underdiagnosed.
https://www.ahajournals.org/doi/full/10.1161/01.hyp.00001016...
This isn't as earth shaking as you imagine. The minimum AHI for diagnosis (in the US) IS 5. 20ahi (meaning you stop breathing 20 times per hour on average), is pretty mild. Some people have ahi over 100. Meaning a 26% decrease isn't actually doing much for you.
What I can tell you is that I know several people who seem to have sleep apnea, complaining about the symptoms, who were told by their PCP that they don't need a sleep study because they weren't fat. When your partner complains about you choking in your sleep all night, you probably should a get it checked out regardless of your BMI. I honestly believe that doing a sleep study once every couple of years should be considered routine for everyone. We check our eyes, blood pressure, testicles, skin... Why not check for sleep quality prophylactically?
I'm not saying you're wrong, but the OP using the condition as proof of societal causes of sleep issues is way off the mark. Skinny people can experience it. Children experience it. Bodybuilders are quite prone to it. As tissues loosen and sag with age across the body, old people are prone to it.
I have sleep apnea and am one of the most fit people I know. When I was in the military, I encouraged many of my friends who sleep poorly to get a sleep test and many of them - fit and young - were surprised to learn they also had it. I would not be surprised if some significant portion of the population has it and is just unaware. At anything short of severe levels, many people would never even suspect they have it.
Sleep apnea is one of the most diagnosed conditions in service members separating or retiring from the military
This means an extra $1-2 thousand per month for life in most cases. So there is this natural experiment where we have a population with a very high incentive to get tested compared to the baseline population.
Because the toll that way of life takes on your body is at least a magnitude more than most civilians realize.
Years of little sleep in poor condition while under constant low level stress, being in unfamiliar conditions where you never quite feel safe sleeping, constant interruptions because the military activities don't stop while YOU sleep, poor temperature control (hot or cold), poor hygiene availability, poor sleeping surfaces, odd work schedules, short sleeping schedules...
Those are just the factors that you deal with for decades that relate to sleep. I wasn't a grunt; I did do a lot of move fast and don't break things or people die stuff (Nuclear Power, SAR Aviation, Amphibious Operations) and that was just how life was.
We had a few overweight people, but they were the exception. Those of us who were more senior were just all broken in so many ways. I don't THINK I have sleep apnea, but I do have trouble sleeping from the pain I'm in every night from a back injury and multiple autoimmune issues that cause flareups and pain.
The cost on those that serve is absolutely astounding. I don't recommend service to anyone.
There are also a lot of other causes of sleep apnea, physiology being a big one, also obstructions in the nasal canal.
Sleep apnea is not because you have fat in your neck obstructing your airway but your tongue relaxing at night and the area below the uvula falling backwards then obstructing your airway.