Because you can go 3/0 in lane and by the 10 minute mark, your mid will be 1/10 and your jungler will be 0/6, having fed 2 deaths to each lane.
And then, of course, you'll lose the same LP as them, or MORE if you are a higher rank than your teammates. What a FANTASTIC ranked system we have riot.
This jungler going 0/6 was actually worse than the jungler I had the previous game, who was AFK the entire game.
And you wonder why so many people are losing interrest in your game. You don't need to keep reworking champs and runes, YOU NEED TO FIX THIS CRAP.