I think many people have something to contribute though I wouldn't say "everyone".
The guy who taught me most of what I know is probably Nestharus.
However there are other guys I want to mention:
Anitarf, has taught me to look at things differently and to not to go blindfolded into speedfreak mode.
WaterKnight and Troll-Brain have taught me that I don't know **** about JASS.
Vexorian wrote JassHelper and regardless of how he codes many of us are using the program he made. Of course you have to credit the people who helped him develop the project as a whole... vJass, NewGen, and their components... but none of those guys are really around any more.
There were a lot of people coding better than me before I even knew what JASS was. In fact, vJass's last update/hashtable intro were there before I even started coding.
The people that make healthy coders should have two main charactertics:
Motivated to learn (most important).
Be careful to not go too far with the speedfreak mentality. Efficiency is good but too much is like a drug. Many things need to be optimized, but less than some might think.