Half of pos 4 players are literally trolling, so if you play pos 4 yourself then you have a huge headstart in most games as the enemy will likely have someone not playing seriously.
Pos 4's are half the time playing pudge, mirana or spirit breaker and run around with boots and 5 empty slots while just soaking xp until they can start to have fun with their hero.
Some will play hoodwink and buy strictly carry items.
Others will play earthshaker and also sit behind you for XP, and make no attempts to use his HP pool to trade with the enemy.
I just had a Dazzle going double bracer, treads, ogre axe 4-0-4 build.
If you queue as pos 4 yourself and play your role, and try to win the lane, and try to give the offlaner a good game, screw with the enemy carry and pos 5, then the game should be winning already.
Source: https://www.reddit.com/r/DotA2/comments/1898oef/pos_4_is_the_easiest_role_to_climb_mmr_with/
