Can you name the other 50?
Without looking, and apart from the GPL license, can you name the other 50 licenses approved by the OSI?
Who cares, it's GPL2 for open source, GPL3 for patent protection on your open source. It could be 50 or 5000 licenses approved by the OSI, nobody cares the only people who use those other licenses are the companies that wrote those other licenses. It's just noise, nothing but noise.