>>714486325More than likely all assets and code are stored by the devs or copyright owners. They won't destroy stuff potentially usable in other projects. Code, assets, etc are already made/paid for, and it'd be stupid to toss. Not to mention, if they decide to pass the project on to another developer for some reason later. Shit happens all the time.
Assets don't take up a lot of space. Not even a full hard drive on absolute egregious circumstances. I've got my 7TB DEV drive with hundreds of thousands of sound effects, texture packs, uncompressed artwork and personal stuff.