I've been thinking a lot about the uselessness of kiruv lately and I came up with a theory about a life, here goes:
Hashem has made a set balance of good and bad, frum and not frum, light and dark etc, and so, the more kiruv you do, and the more people you "make" frum, it becomes equivalent to the amount of people who go off the derech.
This idea of a balance has come to me after a lot of observance and consideration of random nonsense I've heard at shuirim, so here goes:
1- I've mentioned this time and time again, the OTD rate is ridiculously high. All the Rebbeim are flipping out. I've heard that BT communities have more men (men become frummer at a higher rate than women do), and similarly, the men go OTD more often than woman do (one of the many reasons they kvetch about a "shidduch crisis").
Right there is a direct show of the "necessity" of kiruv- try to root new flowers, and in return you kill the ones already rooted...
2- Many shuirim and many tshuva speeches I attended (like before Rosh Hoshanah and Yom Kippur) I heard that if you want Hashem to bring moshiach, you yourself, and only yourself, have to change your actions to fulfill more mitzvahs, and spread goodness, because one cannot change the actions of others. The idea is if you do good deeds, not only are you bettering yourself, but you're setting an example for others to become good.
If these shuirim are in actuality preaching what hashem wants, then commercial kiruv (oorah, ncsy, l'man achai etc) is a complete waste of time. To create specific programs, exclusive to potential BT's, we are only defeating the purpose of the concept of "lead by example"
3- The purpose of kiruv, is often, to make others return to Judaism. One of the main ROOT reasons for doing this, is to bring moshiach quicker. Often commercial kiruv organizations use manipulative skills to turn people. They begin to twist works of literature to show how corrupted society is, while ignoring all the abuse and whore-like behavior in the bible. They also point to everything in the "outside world" and compare it to the goodness of the religious world. This once again defeats the purpose of "lead by example" that I mentioned in #2, and also defeats the entire concept of accepting people as individuals. Once the label "frum" is given to you, and you begin to dress and live-by the label (even in a modern sense), you must act in a certain way in public to avoid a chillul hashem, when you're not frum, you have the freedom to do as you choose, on the individual basis. Unfortunately for us, we have many frum people, who are full of crap, and many non-frum people who aren't (instead of it being vice-versa). If we judge by someone's "frumness" we're really overlooking the way they handle their man-to-man relationships and only focusing on their lack of substantial man-to-gd relationship (or what appears to be lack of, that is too private for us to judge).
I personally would trust more non-frum people with election ballots than I would frum ones. Frum people have agenda's for everything and are often backstabbing liars.
So, we have a balance of frum people who act like a$$es in their man -to-man relationships as well as non frum people who act like mentche's in their man-to-man.
The concept of kiruv kills any balance we have in this world. It's there for a reason. We'll always have people go off the derech, just like we'll always have people convert and turn BT, and that is because we have a balance in this world.