You made up a situation which doesn't fit the original question, and tried to use that to refute it. Yes, the photosynthesis example doesn't need a "normally," so all that means is that you can't use it for #1.
"Normally, you will get cavities if you don't brush." The qualifier "if" is necessary because cavities aren't a guarantee.
"Xenogears is normally a life-changing experience if you're open-minded." It's normal for open-minded people to have their life change, but it will not always happen.
The first condition ISN'T absolute. The tresulum is only "frequently" overfesked. Furthermore, a wizard could easily level up enough to defeat a dragon. Assuming the power of his spells increases exponentionally, the wizard would more frequently win. Of course, that's only if more high-level wizards fight dragons.
I wanted to do #4 but I got nothin'. There's no reason to assume that a shared word indicated primary use, unless the "in frumpaling" part is the real hint.