Best selling doesn't make it the best. Canon has sold boatloads of its various EOS and Rebel cameras. Good cameras? Yes. Best cameras? Maybe, but probably not, especially with their entry level cameras.
I think trying to nail down the best camera ever would be dIifficult, maybe impossible, to decide. Best made? Best features? Best lenses? Easiest to use? And nearly everyone has different opinions on what they think would be the best.
I could list maybe 10 cameras that I think might be the best, and they're all different from each other.