Not at all. Nintendo doesn't have a patent on their hinge, there is absolutely nothing preventing anyone from having a multi-stage hinge like on the DS except one thing: money.
ED said that he could have designed a hinge from scratch to be multi-stage, but doing so was prohibitively expensive. He had to go with an off-the-shelf part. The part he selected is compatible with the 3DS hinge, so you can actually buy a 3DS (I think it was the old style phat one, someone correct me if it was the lite) and replace it yourself. He wasn't able to include the 3DS hinge because, even though they don't own a patent they do own the copyright on that particular design, so manufacturers can't just sell them off-the-shelf to someone not-Nintendo.
If there were a non-Nintendo multi-stage hinge, or even ones with different angles available off-the-shelf then he could use them. Sadly he's got to go with what is available, which is a 170 degree lock. It's the market, one just doesn't really exist.