Manufacturers being unrealistic should not be an issue. The publicized numbers are generally determined by actual testing under conditions specified by regulatory agencies, like EPA. It's a little odd that the Tesla Model S outscores the I-Pace on the EPA range test, but the I-Pace wins hands-down on an independent test methodology. Not impossible, but suspicious. My guess is that either Tesla cheats - a lot!!! - on their EPA result reporting, or the independent tester somehow got hold of a bad Model S.
200 miles of real range is my requirement also, and that's exactly what I got on my Chevy Bolt.
This independent test may provide some encouragement for those who have been concerned about the I-Pace' range. I'm not worried, I believe it will be fine for me.