@SpacyRicochet sorry for tagging you in reply to a comment from three months ago, but you asked an interesting question that I actually think I have an answer to!
My theory on the long-ass titles is that they're actually just non-titles. They're essentially mini descriptions of the premise of the story. It makes a lot more sense when you picture a lone web novel sitting in a forum trying to catch people's attention. The author thought of a story but no title, but obviously needed a title for their forum post, so they just wrote up whatever and sent it out into the world.
Why the authors aren't made to come up with real titles when they make it big and get published is anyone's guess; but I think it might be rooted in the Japanese language and its propensity for shortening even the longest of concepts into four syllable nicknames. These four syllable abbreviations are so common that they're an irreplaceable part of fandom in Japan, with published mangaka even considering what the abbreviation will look like when picking a title, or choosing one they like right from the beginning and advertising it to the fans for it to catch on.
In English, we abbreviate and create shorthand by taking the first letter of every word, and turning that into an acronym, such as "Fullmetal Alchemist" being shortened to "FMA". (The Japanese nickname for FMA is "hagaren", from the full title "hagane no renkinjutsushi".) So naturally, the longer the title of something, the longer the acronym. But these Japanese nicknames always keep their four syllable format, and people will always use them to refer to a work, regardless of how long or short the title is. So overall there's just a lot less reason to keep titles to a reasonable length.