Blender was commercial software that cost money. After the company went bankrupt, the former CEO and a bunch of Blender users got together and raised enough money to buy out the source code and made it open source.

I don't think Blender can really be called a clone of anything other than in the most superficial sense. Certainly when Blender was first being release it looked and worked like nothing else in the industry, often much to its detriment.