I Believe this is Why We See Movement in Membership...
That said I recognize that not everyone is where I am intellectually, but also that many people who might not crave the same depth in theology might have a deeper prayer life than me.
It is hard to balance speaking to deeper issues that some more maturing Christians desire while also allowing the message to speak to newcomers and spiritual infants as well.
As leaders we get pulled in all kinds of directions. (AMEN, well said) Not every believer is ready for a six point study on the doctrine of priesthood of the believer. They need it, but they might not be ready for it. Too often I've found that if some individuals continually remain in a near infantile state they have some other problems at hand than just being able to process theology.
(You are right on this point. An infant is cute and cuddly for only so long. If that infant does begin to show growth, a doctors visit is needed to determine if there is a mecial issue. Thus the same can be said for belieers that remain infants forever)
Finding our spots is important. That is one of the reasons I'm engaged with multiple forums over which I post deeper theology and philosophy. I love these conversations (even though they are limited.) Its a place of leveraging my interests.
The weird thing about church is that it brings together people of all social levels, all educational levels, and all vocational levels into a diverse community and (usually) forces them to find stuff in common. It is something that we generally don't do on our own. However, it is worth it when we work at it.
...there are churches that preach the Gospel of salvation so good, that they can get people to the altar, but after those folks grow in the Word and their hunger for more information on God grows, they search and find another church that feeds their new-found hunger.
One such church that is great at getting them to the altar is the Calvary Chapel group; however, I've been in churches where some of our better workers have transitioned fro CC to our church, because they needed to grow and CC wasn't feeding that hunger [with more deep seated theological teaching of the Scripture].
A lot of pastors may get squeamish [egotistically speaking of course] the thought of losing members, but I've always called it "Blessed subtraction" because when people grow as far as your theological teaching is going to take them, it is like moving from elementary school to junior high, to senior high, to college, to graduate school.
Some people never grow
[see my note in pij comments above about infants that never grow]. Others desire what one church can no longer provide, which is why I always encouraged those folks to seek out new surroundings that meets their spiritual needs, and challenges their spirits to grow further than my church can take them.
Sometimes, a good pastor can meet that hunger throgh Bible studies, and even bringing in pastors or lay pastors who have knowledge of theology the pastors may lack, and putting them in charge of teaching subjects throough classes offered by the church.
If the church is doing its job, people will come and people will go, it's just important that we never let people simply drop out of fellowship, which is why a pastor's heart must also include a shepherd's eyes.
Sound, progressive theology should always be something a pastor strives to teach, but, like you said,
pastors can't be everything to everyone; so when a family or member hit the wall and want to move further [theologically speaking] it is the pastor's job to help them grow further and at times that may be helping them to find a good place to nuture their hunger and help them to continue to grow.
This is my opinion, and many see it differently, but when I served as a full time pastor, I never took it personal when a family let me know they had to move on. I felt like I had done my job to my best ability, and they were in need of someone who would be able and capable of taking them to another level, theologically speaking.
Migration in the pews can and always will be part of any teaching church. After all, "Iron sharpens Iron!" Even if it's not always
us that continue to sharpen that particular piece of iron.