I think you're reading into the term "utopia" too much. The experiment was a utopia of the body perhaps where there are no biological needs that aren't satisfied with no external forces of nature acting to reduce population aside from the size of the habitat that the rats lived in - as you mention we do not live in a utopia as people do grow hungry and are lacking jobs.
It also was not a utopia because the rats clearly where not happy.
I'd disagree and say that in overpopulated areas there is a higher rate of depression, obesity and psychological problems than in places with lower populations - but I haven't provided numbers there and neither have you - so both of our arguments are anecdotal.
As an aside I was more referencing the hikikomori phenomenon when I mentioned NEET's - whilst they are NEET, they are extreme cases of social withdrawl and other mental problems.
It also was not a utopia because the rats clearly where not happy.
I'd disagree and say that in overpopulated areas there is a higher rate of depression, obesity and psychological problems than in places with lower populations - but I haven't provided numbers there and neither have you - so both of our arguments are anecdotal.
As an aside I was more referencing the hikikomori phenomenon when I mentioned NEET's - whilst they are NEET, they are extreme cases of social withdrawl and other mental problems.
https://en.wikipedia.org/wiki/Hikikomori