I suppose I see the point of the idea of 'downsizing', but I would word it differently.
For me, my work box is the perfect size, and I wouldn't change a thing there.
At home, however, it's just a mess. Useful tools, things I no longer need at work, 'maybe-someday-this-will-come-in-handy' tools, renovation leftovers, freebies, etc.
A lot of times for me it comes down not to where to store the tool, but if I should even have the tool. Fortunately I'm not as much of a 'collector' as some of the guys around here, but it's a pervasive problem nonetheless.
The goal I would have isn't just to have more storage or less storage, but to have the right blend of storage solutions for the ideal amount of tools/parts/junk for your needs. I've donated a lot of surplus tools recently. It was all useful, which is why I had such a hard time getting rid of it, but I eventually came around to the idea of placing a higher value on empty space and the ability to move around versus having duplicates of everything, 'just in case'. Because I had fewer tools, I was able to donate the cabinets that were storing those extras, freeing up floor space.
It's a balance. Sometimes less is more.