Myself, I am very "getting my hands dirty"-oriented, and the corporate onboarding goes over very poorly with me too. Sit through multiple days of material that is dumbed down to the company's lowest common denominator. Having to be giddy with other new hires in departments that you will never have any interaction with anymore. Kill me now. So, if the trainers just go through the motions, why wouldn't the original poster and I just put in the mere minimum to get through it, and start my real job...?
Oh, my real job... in the cafetaria with no desk? So, sure, the manager can forget to put the request in. But would a manager not know that you start, schedule a welcome meeting with you on the first day, touch base a few times in your first week? Plenty of chances, still no desk! It's ridiculous, but I am not surprised. If you don't think that is ridiculous, then, I don't know, maybe you've been conditioned to that sort of environment. With no snark I wish you much joy in your employment there, but then please let the original poster and myself move on^H^H^H^H^H^H^Hrun for the hills.
Here's what onboarding should look like for an Engineering role: you come in at 9:00, do the bare minimum with HR, meet your team, set up your computer, and before the end of your first day, you have your first code changes in production. Then you go home with a feeling of accomplishment. Then, during the rest of the week, some onboarding meetings will happen, but at least you have started with the most important place: your team.