Maybe I got a bit unlucky, perhaps you got a bit lucky. Presumably you're quite good too so might have only taken a couple games for you to leave behind the unwashed masses. It is quite bad down there.
Well if Dota buff is accurate he left the trenches after game number 2.
His first game he had 2nd highest GPM/XPM and tower damage.
His second game he had highest GPM/XPM and tower damage. 5 times more tower damage than anyone in his team and more tower damage than all his allies combined.
Very small sample size but no reason why he cannot maintain over 4k if his main is stable around there. His smurf might even enter a higher MMR after the initial 10 ranked games.