Please note that I'm only trying to start a discussion here; I mean to cause no offense.
No offence taken, this is a good question and often understood very poorly by people in our community.
How can we not wander if we do not have a living leader to guide us? I believe that we need a living guru for Sikhism to flourish and to adapt to the reality of today; a religion that is unchanging is a religion that is dead; while a religion which is always being added to is one that lives.
Well you see the thing is, we do actually have a living leader to guide us. It's called the Khalsa Panth. The collective body of Baptized Sikh men and women. Sikhi's leaders.
Guru Gobind Singh ji's last words were actually closer to the effect of "The (Adi) Granth is the Mind of the Guru (contains the Spiritual Light of all 10 Masters) and the Khalsa is the Body of the Guru (Political Authority and decision-making power within Sikhi)."
Sikhi is not an "unchanging religion". The Khalsa literally have the right to create, amend and destroy ritualism and practices as they see fit. They have the power to alter the Rehat Maryada in order to accommodate the changing needs of the Sikh community in each new generation.
regarding a book in the same way you would a human being strikes me as superstition.
You are confusing two different things. The ritualism the Gurus criticized is very different to the ritualism of the Khalsa. The Gurus specifically spoke out against believing ritualism and performing certain holy acts would make you better than others, and that only through Naam can one experience true spiritual liberation.
The ritualism of the Khalsa has nothing to do with spirituality. It is intended to provide a distinct identity. Guru Gobind Singh ji didn't say "keeping your hair makes you better than everyone else." Thwe point of the 5 K's and the regulations in the SRM are to preserve the distinctiveness and sovereignty of the Khalsa from the rest of the religions in the world.
As for treating SGGS ji like an actual living Guru, I suppose that is something the Panth has decided they wish to do. There needs to be a certain standard for our entire community to adhere to when handling the spiritual light of the 10 Masters and at some point, the Panth may have decided that standard is to treat SGGS ji with the same respect we would treat the human Gurus. This is not a spiritual act (which the Gurus would have spoken out against), but a measure of respect our Panth has agreed to adhere to. These regulations are necessary to ensure that our entire Panth meets a certain standard when handling our Guru.