Having lived in Berlin and Stockholm (and a few other cities), I'd say Stockholm has by far the worst kebab options of all places I've lived, while Berlin was the best one.
I'm curious whether this is reflected in local reviews, or whether the locals just lower or heighten their standards based on the what the average food quality is like.
I'm not sure about Stockholm, or Sweden in general, when it comes to kebabs, but kebabs in Norway bear little resemblance to the kebabs I get in London. And the UK now has a chain serving "German" kebabs, which again are significantly different from the kebabs we get from Turkish takeaway places and restaurants here... It's not that they're better or worse - I might crave one or the other depending on what I'm in the mood for, as they're almost different dishes.
So, comparing cities against each other is a lot harder than comparing differences in local opinion by location within a city.
Good, but different.
London of course has the two styles, |Turkish| and Turkish via Germany.
Before that, Kebap was a dish served on a plate, taken in a seated manner.
Verdict
NO
The Döner Kebab was not invented in Berlin.
Popularised here? Ok.
But there are no participation trophies for that.
Turkish immigrants introduced it in Germany in 70's. However it is true that the current version of Doner kebap in Germany is quite different than Turkish counterparts. (Sauces, toppings etc)
It is true that in Turkey, you'll find the Döner Iskendar (cubes of bread, covered in döner meat, covered in sauce, on a plate) as a very common dish, but to claim that the street food variant was new in the 70's is insane. There are a ton of people alive today who can refute that, trivially.
I don't want to find out how bad the kebabs are in Sweden and other places you hear the from like some US cities if you think Berlin kebab is high quality in comparison.
I know getting something on the same level as Rüyam would be impossible; but I would pay a not-insignificant money for something resembling a random Bude near my old place.
I now live in Malmö, which has a much higher number of people from Middle-Eastern countries, so their cuisine is also a lot better than what you can get in Stockholm. However, since I've also become vegetarian in the intervening years I could not tell you what the local quality of the kebab is. Falafel is pretty passable though. And one of my Iraqi friends has said the better places in Malmö win the "least disappointing experience in Sweden compared to home" award, for what it's worth.
I'm sure you can also get amazing specimen in Arab countries and in Turkey (I don't have first hand experience there).
This is frankly odd, given that for most cuisines I can point at some other place surpassing the original. The best Italian food I've had has been in Chicago, the best Mexican food I've had is in San Diego. You can find extremely good authentic Chinese food in the Bay Area if you know where to look, but I can't say I've covered enough of China to confidently decide a winner there.
At least in Germany I suspect it has something to do with Germans considering it cheap fast food and as such are very price sensitive - there's only so much you can do when you have to cut every expense as much as possible.
Shawarma is basically a variation of the same dish:
"The shawarma technique—grilling a vertical stack of meat slices and cutting it off as it cooks—first appeared in the Ottoman Empire in the 19th century in the form of döner kebab,[1][14][15] which both the Greek gyros and the Levantine shawarma are derived from."