Canon and Nikon are leaders in the camera business because they have been making cameras much longer than other brands. While Panasonic was busy making white plastic cased AM/FM radios, Nikon was being selected as the camera system that would be carried and used on each and every NASA space mission...in the 60's, 70's,809's,90's,2000's, and the 2010's...so basically, 60 years' worth of deployment on NASA space missions...
Panasonic? Makes a nice electric shaving cream heating device, or so I hear...
Panasonic's new 4/3 system cameras are 25 years newer than some of the Nikkor lenses I use on a regular basis...market leadership on the part of Canon and Nikon has been built over the past five decades...while the 4/3 system has barely been on the market for five years now. It's very cute stuff though, the 4/3 stuff. Too bad the sensors are so tiny,and everything looks like a deep depth of field snapshot unless one uses a $900 uber-speed prime lens...