We're a tiny market. The biggest cost of any device like this is the fixed cost of developing software etc. The massive sales of 100 or so worldwide are unlikely to be a huge investment.

FWIW, there's a very nice device that a lot of power pilots like, the Stratus 2. It ain't $70, and the software is another $75 a year, but anyone who's willing to risk IMC should probably be willing to spend more than $70 anyway.