I think you are right on this. Our economic system absolutely requires growth. I am at heart a capitalist but I often wonder how long this can go on. Earlier I compared us to a cancer that grows uncontrollably until it kills the host organism and sadly I think if we can't tweak our economic system to not rely on growth that is exactly what we are and what we will do.
I think the requirement for growth is based, at least in part, on the fact that our population keeps growing. In the US and maybe Canada, our population is growing due to immigration. Without immigration we would be like Japan and many Western European countries and have negative population growth.
Part of the "need" for growth is based upon the very human fact that most people want more, aka, they are greedy. This is not only the rich or corporations, but almost everyone. In the US, Canada, Japan and most of Western Europe, we do not have a problem with meeting basic needs, unlike much of the rest of the world. We want more because we want it, not need it.
Most of the worlds population growth is in poor, un-modernized nations. Most of these nations have one of three factors in common, closed "protectionist" economic systems, politically unstable area or socialist based systems, all hinder advancement, development, and the adoption of modern techniques. Most of their industry, including agriculture is still human/animal powered which requires large numbers to accomplish and you barely break even, if you do. They do not have the economic strength to make advancements themselves but block/discourage outside investment which would allow growth.
Religion is of course another major cause of population growth in many poor nations. Take a look at how many are Catholic or Muslim. Male dominated societies where women are given very little say in reproduction rights, often, like Muslims, this factor is aggravated by religion, is another reason for uncontrolled growth.