Can economic growth be eternal?
Possibly, with creativity.
But, you see, the true measure of economic activity has always been happiness, not dollars.
And happiness can always improve.
Passing around more stuff, on the hand, doesn't guarantee a better life.
And the numbers we attribute to these things (dollars) cannot be directly correlated with happiness.
Yes, we should seek to help the disadvantageous, for their sake and ours, but let's not make a number (GDP) into some kind of God.
Other measures are more appropriate and important and measure freedom, happiness, opportunity etc. Something GDP cannot do.
It just isn't that simple.