>>IMO, the biggest problem is software startups unwillingness to hire other types of engineers.

>>It's easy to bridge from Arduino to Atmel AVR IF you know how to do board layout. Startups need to either grow their knowledge of electronics or hire some electrical engineers.

I agree, hardware can not agile like software is. So you have to re-design your product from prototype(like Arduino).

Even more, you should outsource your hardware design to other professional hardware company, such as design house.