Back in the PS2 era of game development, we didn't have much of virtual machines to work with. And, making a shippable build involved wacky custom hardware that wouldn't work in a VM anyway. So, instead we had The Build Machine.

The Build Machine would be used to make The Gold Master Disc. A physical DVD that would be shipped to the publisher to be reproduced hopefully millions of times. Getting The Gold Master Disc to a shippable state would usually take weeks because it involved burning a custom disc format for each build and there was usually no way to debug other than watching what happened on the game screen.

When The Gold Master Disc was finally finalized, The Build Machine would be powered down, unplugged, labeled "This is the machine that made The Gold Master Disc for Game XYZ. DO NOT DISCARD. Do not power on without express permission from the CTO." and archived in the basement forever. Or, until the company shut down. Then, who knows what happens to it.

But, there was always a chance that the publisher or Sony would come back and request to make a change for 1.0.1 version because of some subtle issue that was found later. You don't want to take any chances starting the build process over on a different machine. You make the minimal changes possible on The Build Machine and you get The Gold Master Disc 1.0.1 out ASAP.