Compared to hundreds of studies about green tea extracts, many of them reported by the media, those population-wide studies had minimal effects on the public. And even those studies would usually find the largest effects on people who drink impractically large amounts of green tea, e.g. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3103781/ or http://annals.org/aim/fullarticle/722554/relationship-betwee... (6 cups per day!). In addition, there are many confounding factors with population-wide studies compared to clinical studies.

Honestly its not impractical if you just replace your coffee with it. I probably average over 6 cups per day, and don’t really do it out of any health concern at all.

6 cups of green tea per day isn't anything unusual. There's always tea ready at home (my wife is Japanese). And at work I drink much more coffee than 3 (normal) cups. I don't drink coffee at home though. But I'm getting a lot of green (and other) tea instead.

I drink about 1,5 liters of green tea nearly every day, nothing impractical about it.

Population studies don't have control groups and are largely worthless for recommending supplementation. There are just too many confounding factors.