> If you want to license your software under a proprietary license, just license it under a proprietary license.

It's not that simple. I'm about to come out with a 3d-printed product that will sell in a similar market to 3d printers. My product is begging to be open-source hardware since anyone with a 3d-printer can create a large part of it and I'd be ecstatic (and richer) if the product developed a community of followers.

However, MakerBot did this and it was a mistake. Clones quickly came out of china at half the price. MakerBot ended the open-source and developed newer products. My outfit is not big enough to do something like this.

So I have considered using a commons-based license. Makers can play with my product without others undercutting my prices.