i asked this question on another question/answer forum and received a really great answer - i wanted to share with you all:

question:
Why is communication between planes of existence so challenging? Why isn't it as easy as making a phone call? So many people out there who do not believe there is more to life after death, and only if it were as easy as a phone call, it could completely change our collective outlook. 

answer:
We have chosen to incarnate onto this Earth plane at this time because of its characteristics. It has extreme cruelty and tragedy on the one hand, and compassion and love on the other. It is a transition period in which humankind is poised to become more loving and connected to the Source. But we who see that are not now major forces on the Earth plane. That will come.

And so, during the period before this time and today among most people, there is great ignorance about spiritual matters. For society at large, we are in a spiritual deadzone. That is why we aren't able to communicate more freely with those on the other planes of life. But we chose to incarnate into this period of Earth's history, so the ignorance is something important to help us learn the lessons we need to learn.

It would seem that we need to feel this separation from the other planes of life and fear of death as the end of existence to learn how to trust, love, and connect. We are the ones keeping the door shut that could freely swing open. We must learn and be different for the communication to occur. We are making the choices.

However, we're moving toward a time when communication with those on the next planes of life will be easier and more commonplace. That is beginning to happen now. And when people are commonly communicating with those on the next planes of life, it will be another Earth plane period, and we may choose to incarnate into it to learn the unique lessons that period can teach us. We are helping to develop the new Earth plane now, and we later may decide to reap the benefits by incarnating back into that later period where people are more loving and compassionate, are open and listening to the Source, and can communicate more easily and freely with other planes.

Love and peace, Craig