I don't speak for the project but there are several reasons not to.
First, as Brian touched on, there's no compelling reason to produce hardware. There would have to be something significant and not available elsewhere to justify building hardware. Most of the suggestions I've seen have to do with things like adding more IO ports.
Second, it's a lot of work. Not so much designing a board, but producing it. Several people would pretty much have to dedicate themselves to building, selling, and shipping the product.
Third, outside of China it's very expensive to build boards. I can buy whole assembled boards from China for less than I can buy the main chip on them in the US. I looked at building a V9 gps for myself and the BOM cost went over $25 without the gps module. All told in the US it would probably be $45-50 in parts for one. If you're building them to sell then quantity 100 is the first reasonable price break on the parts. That means someone has to front $4500-5000 for parts plus the labor to build and ship the boards.
In short, I don't see it happening and hope that the project doesn't try to produce hardware. It's better served by porting the software to other people's hardware like the Sparky2 port that's being worked on.