In German, we have the formal "Sie" and the informal "du". The formal means of address is dying incredibly fast. It's been a huge change just in the past 10 years or so. I'm not a linguist, but I'm pretty sure this is due to the influence of English, which is everywhere.
Just as an example: as a gray-haired professor, I use "du" and my first name with my students. I may be an outlier in my generation, but that is entirely normal for younger colleagues. 10 years ago, that would have been...strange. 20 years ago, it was unheard of.
I used “Sie” with my now mother- and father-in-law until the first time I visited them after we got engaged and my mother-in-law brought out a bottle of sparkling wine and asked if we could be on “du” terms. That was when I started using their first names.
That was in 2008, and was, from what I gather, already rather old-fashioned. It was common enough in the past that there’s a verb for it that my mother-in-law used when making the offer: duzen.
I think English definitely has it's influence but I think another big factor is the general idea that this hierarchic thinking just gets outdated and younger Germans strive to have a sense of equality.
Just as an example: as a gray-haired professor, I use "du" and my first name with my students. I may be an outlier in my generation, but that is entirely normal for younger colleagues. 10 years ago, that would have been...strange. 20 years ago, it was unheard of.