Personal story time, few months back me and my buddy got asked to help our non-dota friend get into the game. We are both playing occasionally in lower brackets.
Both of us created new account to so that noobie wouldn't be thrown into deep water right away. Note that me and my friend were 'baby sitting' - playing neutrally not trying to win vs lower rated opponents.
Out of 10 games 7 had hardcore smurfs in them. People in stack dominating their lanes. I don't see how anyone new and without any friends could possibly survived through such acid pool.
Imagine you are starting to play chess and 7/10 opponents are rated master and will crush you. And its kind of crush that you can't really learn from either.
I really don't see how dota can grow when there are so many alternatives.