Each version up thru Win8 had a style guide. If you wanted the windows sticker on your box you made it consistent. Why would you want that sticker? If you did not have it it was much harder to get floor space at many of the big box stores.

It was at win8 where everyone just noped out and just started doing whatever they wanted. XP/2000 was the last era where anyone really cared.

3.0 to server 2008 which makes that period 18 years.