Curious,
How can one do one without the other? Without Christ there is not heaven, how can one "live for heaven" and not for Christ?
Perhaps, they are not winning them to the Heaven where Christ reigns as supreme Lord of Lords and King of Kings? Many religions have a "heaven" of sorts where you must do A and/or B and you may well get there, etc. etc. But since Christianity is not a religion it is an expression of the life of Christ that lives within you; then those who practice such a life may not be living for either the heaven of Christ or the Christ of heaven?
Do you suppose that it would be fair to say that people who merely attend church are trying to attend the feast without a wedding garment?