That sentence you quoted makes absolutely no sense.
"midwest people complain about happiness, said they would be happier under california sun"
"california people said sun makes them happier"
"midwest people are just as happy as california people"
The first 2 bullet points kind of contradict eachother.
No they don't. Just because you think something would make you happy that doesn't mean it actually would or does - at least in terms of extended periods of time.
Plus, that's a whopping 2k people from 3 states. That is a needle in a haystack sample size wise. I'm also just not fond of taking sample sizes so small and then making a broad generalization about the entire population. That happens a lot and those numbers always make me lol.
Samples sizes are a thing not to mention the other published studies like Keller in 2005 and Deniseen in 2008 that have come to the same conclusion. There have also been studies that show that while going from a cloudy day to a sunny day or a humid day to a dry day will make us happier, the effect diminishes the more sunny days a person is exposed to - basically to a point where it doesn't matter at all. Just because you 'lol' at a result that doesn't mean its not valid.
If happiness were the all important aim of humans, I'd imagine more of us would be successful at it.
For generations we were more preoccupied with the survival of our selves and our species (via children) than happiness so I'm not all that surprised we're bad at it.
when i only had enough saved to live on for 1 month, i was happy.
now i have enough saved to live for 15 years, but have not been happy for a long time.
but i am not sure if i would give up the money to be happy again though.
Then maybe its time to slow down a bit and figure out what would make you happy? It would suck to spend all that effort to retire early only to sit around and be unable to figure out "now what?". It's easier said than done as there are quite a few studies showing that retirement leads to a fairly large increase in depression and health issues.
http://iea.org.uk/sites/default/files/publications/files/Work Longer, Live_Healthier.pdf
(40% increase in risk of depression and 60% increase in health risks - largely due to a substantial decrease in physical activity)
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2442377/
In the sample of all labor force participants, the presence of active depression significantly increased the hazard of retirement in both late middle-aged men and women
It would also suck to endure it till you finally get to the point where you can say "I quit my job today and will now be happy!" and then get run over by a bus.
For me I know that I will need some sort of structure if/when I retire early so I'm trying to figure out what would work well and trying to make the journey more pleasant should my retirement plans get cut short by an untimely demise.