There are a two or three vendors casting Ford FE blocks and I can't imagine that the FE market is larger than the Mopar market. I know there are a lot of Ford cars out there but there are not a lot of guys running FE engines. The FE block is pretty close to a Mopar block in a lot of ways so if someone like Bear Blocks can produce a FE block then I don't see any reason a vendor couldn't make Mopar blocks.

I think some of it is just bad luck. For whatever reason the people who so far have chosen to cast Mopar blocks haven't had the talent or the money or the time to make it happen correctly. Cast iron engine blocks are a very well known commodity by now. Millions of them have been cast over the years. The machining process is also well understood. People know what feeds and speeds and tools need to be used to hit the tolerances. It really just boils down to hiring the correct people and throwing enough money at it until the issues are solved.