I was looking to update my photo gear and was searching the B&H Photo website. The Lumix G85 was selling for $697.99 with a 12-60mm kit kens. Meanwhile if you searched the lenses the same kit lens was listed at $497.99. My calculations tell me the camera is only worth $200.00. WOW, what a deal. I was just wondering how sometimes they arrive at the pricing for camera gear.
Kit prices for most anything is cheaper than buying the parts individually.
One theory is rather than taking a $100 profit for the camera and $100 for the lens, they settle for $100 for both.
Then as Joel said, they got you in their camp.
The traditional battle has been between Nikon and Canon.
Once you buy into a brand, you are very unlikely to change, as you have too much invested in the gear.
With m4/3, while the lens mount is interchangeable between Olympus and Panasonic. My primary light/travel lens on my Olympus is a Panasonic 12-60 lens.
But there are limitations to swapping between brands.
The Dual/Sync IS only works with same brand camera and lens. So if you want dual/sync IS, you are stuck to the camera manufacturer's lenses.
So in your case, Panasonic would have you stuck in their camp.