Fuji is perhaps best poised to enable open development -- their pricing structure is more around hardware variations on a common sensor/processing than strict differentiation in capability.
The far future of camera development probably does look like open-source (or, at a minimum, common-versioned closed-source) software/firmware riding on commercially-manufactured hardware platforms (just like computers today). We're not there yet, but the technical success of Magic Lantern shows that the door is open.
A dark-horse entrant like Sigma could, in addition to Fuji, be a hardware vendor that could crack open a "commoditize your competition" market.