It’s not taking 30% and spreading it. It’s we only ever needed to be making 30% of our total being reasonably distributed for everyone to reach those standards.

I don't understand what you mean by those two sentences. They seem to be in conflict with each other.

You have 100 coins. To say we need to be making 30% of our total being reasonably distributed means you now have only 70 coins.

"leaving a substantial surplus for additional consumption, public luxury, scientific advancement, and other social investments.”

You had 100 coins and now you have 70. You can still buy luxuries but 30% less than what you had before it was redistributed.