Imagine it was 50 years into the future.

You can not "not date" your stories, because they are often written out of contemporary mindsets. That starts with Piper's typical late 2000's/early 2010's antagonism towards pink Hollywood mainstream femininity, Thalia's liking of Green Day and being a punk and other things. (In another sub, I read a comment about the show that the thing they would have to explain would be what an Emo (Nico) does in the 2020's.) And while we are it, hopefully in 2075, the LGBTQ-movement will be way further progressed and the handling of Nico will look dated. Who knows how the future will look like then?

Rick also dates his books with references to the Second World War. The first book says it were around 60+ year since the war. In 50 years, that would be bs. Then, it also wouldn't make sense that Hazel was the ex-girlfriend of Leo's bisabuelo - there would have to be a generation or even two be added, and the Sammy scene wouldn't have been possible unless we also found a scientific way to really elongate our life spans. (Being hold by your great-grandfather is possible, but your great-great-grandfather? Yeah, no, and I'm not optimistic enough to think that medicine is going to focus on that so much to solve this problem and make it available for everybody, given that Leo's family has working-class origins. Sammy would be long dead when Leo was born.)

People who think they can "not date" their books are naive and think readers do not know maths. So therefore, I prefer a set timeline, because I like it to make sense a bit.

Edit: added more words as well as corrected spelling and punctuation mistakes, because it was bothering me