The middle class becomes rich families because they can buy much more with their wealth. Entire miniature cities can be supplied with the same resources (electricity, water, food, waste) that were previously enough for one family.
At the same time, offenders have been shrunk along with them so that they cost less money. So shrinking creates a solution to the environmental issue, but the gap between rich and poor remains.
Solutions to environmental problems are not necessarily solutions to social problems