An update...
I met with a member of the clergy of a nearby Episcopal church who happen to be the brother of the lady who eliminated the root cause of her sleep apnea (and a host of other issues) and he filled me in on the story.
About 10 years ago his mom was having difficulty with cancer treatment. The sister was very close to her mom and decided to move in and act as caregiver. Over a period of roughly a year the brother watched not only his mom degrade but his sister went from vibrant health and being full of energy to extreme illness.
The list included, the development of high blood pressure, high cholesterol, problems with digestion, anxiety, depression, heart irregularities, muscle cramps, cognitive decline, and sleep issues. Medications were given to lower blood pressure, lower cholesterol, deal with gastric problems, deal with anxiety, deal with depression, the blood pressure medication was changed to deal with heart irregularities and an anticoagulant was added as a caution against stroke. Sleep issues were addressed with drugs until the cardiologist finally suggested a sleep study. This resulted in CPAP treatment.
Mom continued to decline. This was extremely difficult because sister and mom had been very close and as mom lost cognitive ability she looked at sister as a stranger. This broke the sisters heart and while brother tried to comfort her it didn't help much.
Mom finally passed and brother stepped in to help his sister out of the downward spiral that she was in.
With the stress of dealing with mom gone, sister started to improve. Over the next 2+ years her health improved. As she overcame each condition she no longer needed the medications to deal with those symptoms and she continued to improve. Finally the only symptom left was sleep apnea. It sounds like she tried sleeping without the machine for a few nights before doing another sleep study. The sleep study showed an AHI of 0.82, no irregular heart beats, the lowest oxygen desaturation was 92%, no restless leg issues, and basically decent sleep. This is when she officially tossed the CPAP machine.
Unfortunately most of us do not have a sudden stress imposed upon us. Our stress comes on gradually and is probably difficult to identify. In addition the brother (a man of God) pointed out that there was most likely some divine intervention involved in the recovery because he had the whole church praying for her. If you couple divine intervention with lifestyle and diet changes you have a very powerful force for healing.
While this demonstrates that removing the root cause can eliminate the symptom of sleep apnea and a lot of other issues, I think it is an outlier. The stress came on suddenly, she degraded suddenly, the stress was removed suddenly, she recovered quickly. Most of us try to put stress into perspective and don't get totally wrapped up in it.
The one person that is dealing with something similar is Pugsy. Her mom is declining, but I don't see Pugsy in any form of downward spiral. She is as feisty as usual. I am sure the circumstances are different.
On a side note...
The brother asked me what my interest in his sisters story was. I told him about this thread and about how I asked my friends if they were diagnosed with sleep apnea and if any were continuing to use their CPAP machines. Sister was a friend of a friend and shared that she once and sleep apnea but got over it. Several of my friends were not using their machines and I was in search of the "root cause" and what could be done to help my other friends come to grips with their treatment.
When I mentioned "rood cause" the brother broke out laughing uncontrollably. He laughed so hard he had tears streaming from his eyes. I asked him if he was alright and he told me he was working on a sermon and was unable to get it to gel. He never considered the "root cause" and this was the part he was missing. He told me it was divine that I showed up to ask about his sister.
I told him that I wasn't totally to "blame..." There was a whole group of people on the forum that guided me to meet up with him. I guess this means that everyone here is part of divine inspiration...

SpO2 96+% and holding...