You could be in place like Japan where you have lower population, but still productivity growth such that incomes don't decline.
You could also be a place like pretty much everywhere in the world before the Industrial Revolution when the Malthusian Trap was a popular thought - and your population grows but productivity declines. GDP goes up, but you get more miserable. Not great.
I don't think anyone imagines falling incomes as awesome.
Additionally, even if productivity and population decline - the Fed can always devalue money such that your income goes up - even if your situation is getting materially worse.
I don't know why people obsess over population growth. We already don't want to invest in the people we have.
Productivity growth should be the thing we all want. There's not a lot of people that are like: Damn those tractors that stole all the agricultural jobs!
For the most part - we're happy 90% of the population doesn't have to work in agriculture.
If you double some poor saps commute that grows GDP too.
If diverted from savings, this grows current GDP. If diverted from some other category of spending, it’s likely neutral. (If diverted from higher velocity domestic spending into the importation of energy [and exporting of cash], it could even shrink GDP.)
Breaking windows doesn’t generally grow GDP.
The neoliberal version is basically "cost of living goes up, manufacturing of instant waste goes up, the common man gets nothing."
Degrowth without economic decline, means Carmel By the Sea in Ca, or those small towns in the Key West where only the rich can afford to live.
You can put many towns in the SF Bay Area which have actively stalled any growth. They have one thing in common: they are super expensive.
Also degrowth doesn't imply living in rural areas.