Living in working in the Berlin tech world, English is already the official working language in most companies. Even as I german i have no problem with this, my only gripe is that it makes it very hard for my non-german colleagues to learn german.
I'm not sure it is actually an issue, it just feels weird as a French person to discover that French is not even required in your own country.
And why should it be? In big cities people tend to be more adaptive towards this than outside. If you go outside to the country side the situation will rapidly change.
But in every major European capital it is most likely possible to get around on just English.
I always make an effort when in France, Germany and Poland to speak the local language but more often than not the locals speak English much better than I speak their language and after a sentence or two the switch is made. Of course making an effort is appreciated anyway but there definitely is no expectation of being able to hold a full conversation in the language of the place you visit.
Again, I'm not saying this is a bad thing, but this realisation was quite surprising to me
A friend of mine has lived in NL for 3 decades now and still does not speak Dutch, I'm sure he's an exception but he does not seem in any way hindered by this particular inability.
I'm not OP, but also at a Berlin tech company. I always say I'm glad I learned German (in a much smaller city elsewhere in Germany) before moving here. You absolutely can learn German here, and I know people who have, but I also know people who've lived here for years and don't know enough to buy a loaf of bread in a bakery. The problem is that you can get away with it: your colleagues can all speak English (and some of them can't speak Germany, in some workplaces, including mine); as an expat, you probably live in a neighborhood with lots of other expats, where the staff in restaurants and shops speak English (and it's not uncommon for waiters to be unable to speak German); you can make your friends exclusively in expat communities, and if you arrive in Berlin speaking no German, that's a lot easier than integrating into the local community without yet knowing its language. It's especially bad if your accent gives away that English is your native language.
Watercooler talk is usually english unless I am around a group of people where I know that they all speak good german, but that rarely happens tbh. It's more likely to hear another group talking portuguese, spanish or arabic :)
It sucks, because it's harder to learn German, because you don't use it on daily basis. Myself including. But I find it ridiculous that some people after many years are not able to handle A1. Come on.