It's the very basics of capitalism, if you create too much unemployment, the system will collapse. What you need for sustained growth is a large middle class with jobs and money enough to pay for your products. On the other end, making production cheaper and more efficient while keeping the middle class rich enough to consume is what creates economical growth. Luxury items that used to have high production costs and thus be reserved for the rich gets cheaper and becomes available to the lower classes.
With that said, believing that infinite growth is possible in an infinite world is still both unscientific and retarded. While the economical cost of consumtion of luxury goods might decrease due to efficient production, the same is not always true for the ecological cost. At some point we will have to transform to a society where production efficiency increases no longer means that we buy a larger number of iphones every month, where we instead use increased efficiency to work less and increase spare time.
If you ask an scientist working with climate change, i guss he/she would say that we already have passed that point..