As a political science professor of mine once said years ago, World War I is best understood as a point of human development where our ability to invent new ways of killing people outpaced our ability to truly understand and control it.

Prior to WWI, battles were still fought with horses, and those who were senior officers and other military type people had grown up in an ecosystem and culture where a professional knowledge of what did or didn't work was developed on battlefields and contexts that were very, very different from trench warfare. To give up on "going over the top" seems sensible, because we can theorize you'd be shot to pieces, but it would require committing to the idea that warfare was now a totally new ballgame and all of the old strategies that had proven efficacious in past battles (i.e., overwhelming your opponent with sheer numbers) was suddenly no longer viable. Old habits die hard.

I also think on some level that people became their own victims of propaganda and wishful thinking. If you think of your enemy only as idiotic, opportunistic cowards, it becomes more plausible to think they'll turn tail and run when faced with a remarkable show of bravery and force. Given that a lot of the iconography of WWI recruitment centered around every country being the heroes of their own story, and celebrating the valor and courage of young men, it's certainly possible that both at the level of the individual infantrymen and for commanding officers chasing glory and recognition of their own to think that this time a charge will work!. Especially when it always existed as a "Plan B" to the unsavory Plan A of sitting in a disease-filled, wet trench and waiting around for something to change.