Aside from the fact that having all terrorists doing extensive research on their own is as unlikely as what you mentioned before, all religions disappearing, there are two assumptions in your statement that I don't agree with.

First assumption is that every muslim terrorist actually cares about their professed religion more than about their extremist ideas.

Second assumption is that anyone would note the same passages of the Quran and interpret them the same as you. This is never the case with religious books.