Not sure which is more amazing. The bike collection or the idea of a 500 m^2 shed in your backyard.
Definitely the shed.
The bikes simply demonstrate his obedience of the n+1 rule.
There are several important bike collections here in Adelaide. One I know in the Western suburbs is a large collection of SA-made bikes from the early 20 century, all in original (unrestored but generally complete) condition. A few years ago I helped sell a friend's 67-bike collection (mainly early and mid-century British racing and touring bikes) and I came across this collection of locally made bikes in the process. It was fascinating to learn about what made them unique. For instance, because bike builders in Adelaide generally had limited access to fancy lugs, fork crowns etc, most decorative efforts went into beautiful lining and flamboyant, multi-coloured finishes. Some of the faded but still extant paint jobs I saw in this local collection were just amazing.