Usually, support is higher game sense / understanding compared to DPS at the cost of lower mechanics. While DPS is often times worse game understanding and better mechanics.
While there are easier to use DPS available, most people often stick to the harder DPS choices while on Support almost every support has a very easy option of just don’t die, stay alive, keep people up. You’ll often go rather far doing just that.
Its hard for DPS to do the same thing with most of the roster. Part of the game sense thing has to do with position. Supports see EVERYTHING for free. DPS might not always see everything when they play flanker style heroes are zoomed into a scope.