GDP is only relevant due to our debt based monetary system, constant grow is needed to cover the difference between all money in circulation and all debt plus interests outstanding.
Getting rid of our debt based monetary system would get rid of the need for growth and therefore would get rid of the need for immigration and the need to exploit local people and foreign countries for the sake of growth.
When will this finally be realised by everyone?!
Regardless of the monetary system, all surpluses will eventually go to landowners.
The only way for a non-landowner to have a comfortable lifestyle is to outperform everyone else. If everyone becomes more productive, rents rise.
So the nature of land 'ownership' means that being productive isn't enough, you have to be more productive than everyone else, and more productive than last year.
Our feudal system of government ensures we need perpetual growth.
(I suspect that the monetary system is basically the same, allowing rentiers to extract unearned income and collect any surplus production, I just don't understand it well enough).