So how is it possible that there are these people who do not experience the blessings? I believe it's because their hearts are not in the right place. They are doing just that, going through the motions, but they are not fully dedicating their hearts unto God. I feel I can say this because I have sometimes found myself in this state. I live the Gospel, but I forget to ponder on the deep doctrines and the love that comes with every little action we are asked to do. This comes down to the desires of our hearts.
There are in my mind three stages of desire: 1) we think we want something but we do not really understand it, 2) we want something and we know why it is a good thing to want, and 3) we want something good, we understand it, and we are actively seeking after it with our whole souls through prayer, faith, and work. Surely, there are other ways we could look at it, but I find these three to be helpful for me.
It is not enough to simply want to be good, to possess good qualities, or to have good things. We must desire deeply and be willing to commit ourselves. It can be easy to desire something at the first level, but it is a very different thing to reach the third level.
We must desire the best of things at the third level. When you recognize that you should desire something with your whole soul, it makes you a lot more cautious about what kinds of things you give yourself to that deeply.
When we desire the things of God with our whole heart and soul, we are bound to receive them. D&C 11:17 says, "And then, behold, according to your desires, yea, even according to your faith shall it be done unto you." D&C 88:32 also speaks of those who receive less glory from God because they are not "willing to enjoy that which they might have received." What a sad thing that is to me. When I read it though, I feel determined to seek out more light and love from the Lord and to enjoy His blessings.
I suppose this has become a rambley post, mostly because it is a thing deep in my heart that my mind keeps circling around.
I'll stop trying to say things, and instead encourage anyone to view this video. Here, Elder Oaks explains this concept far better than I ever will.