Sleep apnea can be like old pipes that are clogged in multiple areas. If you only open up one area, the pipes will still be clogged (like doing a UPPP). Sometimes you can put in drano to soften the clogging and open up the passageways (like allergy medications), but after years of buildup and accumulation, you have to physically open up all the blocked areas. You can also use a plunger to force the water down the drain (like CPAP), but you know that sooner or later, it’ll get clogged again. The older the pipes, the worse it becomes (old age).
I realize it’s not that great of an analogy, but I couldn’t resist :)