" Show me a hill that someone "needs" a 30 chainring and I will show you a hill where someone is not putting out enough power.
There it is right there! Exactly! why do they not put out enough power? Because it is not available. why is it not available? Because they have not spent enough time and commitment training and dieting. So if the cyclist still wants to climb that particular mountain. they have 2 choices;
1) Stop eating and start training and hope that they have the genetics to achive this goal
2) Employ a mechanical advantage, a smaller gear ratio or in my case a gasoline engine.