Yes. Sony and Canon. I’ll summarise what has happened.
Camera technology is moving at a pace and has most recently been dominated by Nikon and Canon. Several years ago the race was basically around sensors and Megapixels. Who could pack more Megapixels into their cameras.
Subsequently the battle ground has shifted away from DSLR’s to mirrorless cameras. This saw Sony enter the race. They actually make sensors for Nikon. They immediately released a mirrorless camera that really set the cat among the pigeons leaving both Nikon and Canon scrambling. The mirrorless technology allowed for improvements in various camera functions in a smaller lighter body. Sony were able to produce a camera that delivered a high MP count but also had a really clever autofocus system that allowed you to track the eye of a person moving through the frame. It was a game changer for portraiture, sports and nature photographers. Canon have sorted their end recently with the release of a camera model that basically puts them on a par with Sony, if not slightly ahead.
Nikon lagged for a while but were hampered by their F - mount which is basically the hole at the front of the camera. It’s too small. So they developed a new mount and then in a hurry released 2 mirrorless camera models that had some real concerns for some people and really lagged behind Sony on the autofocus front. The lenses were slow coming and delivered in a muddled manner. They had very little pro level glass and it was / still is all too slow. A number of pros jumped ship.
The stupid thing is the cameras still take really stunning images. The camera world is full of people where people “need” the latest gear more than actually taking pictures.
The other killer for all camera manufacturers has been the rise of phone cameras. The day of the casual holiday snapper are gone. People use their phones. This has killed the camera market.