It is mostly cultural. Western titles often prefer single word names, even if they don't really mean anything or are super generic. As an example of generic, look at the Elder Scrolls games. Why is this one called Morrowind? Because it takes place in Morrowind. Why is this one called Skyrim? Because it takes place in Skyrim. Or for nonsensical, what is the infinite in Halo Infinite supposed to mean? What about Fortnite? I get that you can build in it, but what about the nite part?
Hell, just look at the names of the consoles. The Xbox, Xbox 360, Xbox One, Xbox Series X. These are some of the dumbest, nonsense names.
Well there may be an argument made that single word, or short names, market better etc, one thing that is common with Japanese titles, is that they are usually abbreviated. For example, someone in this thread mentioned "Is It Wrong to Try to Pick Up Girls in a Dungeon". But nobody in Japan actually refers to this series this way, it is just abbreviated as danmachi. This is the case with most things, Konosuba, Oreimo, Tensura, Oregairu, etc. They all have long names, but are not referred to by these names. These abbreviations are also used officially. This is much more difficult to do in English, and so it gets lost in translation.
There is a second reason as well. It is true that there are many light novels (often isekai recently...) with very long names. Some of them have been mentioned here. But the reason for this is marketing. If you are in a book store in Japan looking for a light novel to read in the isekai section, there will be probably literally hundreds. And the only thing differentiating them will be their titles. So these series will often have titles that are self descriptive of what it's about to try to catch your attention. "I was a 30 year old guy who got reincarnated as a cute loli girl in a fantasy world and now I go to magic school", there is probably a series with a title like this, but anyway, you already know what it's about just reading the title and that may be enough to catch someone's interest amongst all the other things.
