The problem is that nobody knows how.
Jungle is tough because while they can farm jungle mobs with (hopefully) no interruption, they are always being attacked by them. Plus, said mobs take a few minutes to respawn. If you clear them too quickly, you can be without anything to kill for thirty seconds.
Ganking helps, but the problem is some champions can gank as early as level three, while others can take up until level six to be ready to gank. If all of the enemy laners are fed at that point, you're in trouble.
Support is worse in my book. I heard the saying "you are the carry when the game starts" so many times. This couldn't be anymore wrong.
For one, you aren't supposed to farm, so there goes your income. Items that boost income help, but it's by no means as good as farming. On top of that, your job is to help the carry win. This job can be made impossible if your carry isn't good at all.
Supports are designed to enhance the team's strength, not provide strength of their own. If the rest of the team is crap, then even the best support would be stuck losing.
I don't see fixes to these issues.