Comment by mindcrime

Aren't most licenses "not fully understood" in any reasonable legal sense?

OK, fair enough. Pretend I said "not well understood" instead. The point is, the long-standing, well known licenses that have been around for decades are better understood that some random "I made up my own thing" license. And yes, some of that may be down to just norms and conventions, and yes, not all of these licenses have been tested in court. But I think most people would feel more comfortable using an OSI approved license, and are hesitant to foster the creation of even more licenses.

If nothing else, license proliferation is bad because of the combinatorics of understanding license compatibility issues. Every new license makes the number of permutations that much bigger, and creates more unknown situations.