Incidentally, I've also taken a deep dive into the world of specialty coffee. I've come to the conclusion, that if I want to drink something delightful, coffee will end up being about 5 times more expensive (as in €/l).

I know it's not a fair comparison, since the experience is vastly different, but if you look at the numbers, that's what you'll get. This means that if you spend the same amount on good coffee and good tea, and drink the same volume of both every day, you'll run out of coffee long before you're even half way through your tea stockpile. In reality though, I wouldn't drink a liter of coffee, but I certainly can drink a liter of tea every day. The difference in expenses is significant anyway.

However, if you think about café pricing, that's a whole different ballgame. You aren't just paying for the beverage. If you think about it that way, you can definitely drink really expensive specialty coffee at home, and it's still going to be cheaper. If you switch to tea, the difference gets even bigger. A single cup of Lipton at a café will cost you about as much as a 60 g bag of decent supermarket sencha. Drink that at home and you'll have enough for several weeks.