I imagine it’s a combination of neccesities (to him), magic stuff he needs, and random shite that he has no idea what it is or what to do with it. Very crow-brained behaviour
One remnant of the past is the Softmap building in Akihabara, formerly known as Tsukumo Akihabara Ekimae, with the iconic escalators. Here is was in 1980:
This building has changed hands quite a lot and this has affected it’s techno look for the worse.