GDP increasingly represents abstract activities, stuff that barely has any physical presence. For that reason, there's no physical reason that those activities it should ever really hit a limit. Watching four Netflix movies doesn't cost anyone that much more than watching two.

Demand may hit limits before supply does. Economists assume this isn't true but we don't really know.

Whether there's growth or not is really more about planning how we're going to set up governments to run. A government over the same land for a non-growth society looks very different from one in which there is growth.

One thing that caused the Great Depression was a decline in the supply of money relative to what it "should" have been. That caused deflation.

In that case, there was unnecessary material hardship purely because of basically an error. We live with the memory of the Depression and try to avoid that.