I disagree with "re-learn" statement, people going from ICE car to a Hybrid expect their to be some difference, but when the manufacturer doesn't give any guidance they're going to do what their use to. FORD's solution was to have MPG (Prius) switch to improve FE on 2016 and newer. We don't drive a Mustang the same as F150 truck, each vehicle has it's own driving characteristics. As far as Wayne Gerdis NIRO testing, I talked to Bob, Wayne's co-driver and he said they drove slow and had strong tail wind, not a good comparison. Four out of 5 NIRO's I drove I got a little better than EPA. The 2017 CMAX Titanium got alot better than EPA and little better NIRO Touring's too.
I missed the brake coach on My 2010 FEH with a bar that moved up and down with brake pressure, that been said I still have 98% Life Time Braking Score . On FE the CMAX has more HP so it can use more gas during acceleration, you don't get something for nothing. Bottom line is the CMAX is designed to run in EV 40-60% of the time where as KIA NIRO, Prius V and Hyundai Ioniq use EV to assist the ICE.
As for your first point, you don't relearn how to drive when you buy a new car, you merely adjust your current knowledge to how the new car performs. You learn not to slam down the throttle on your V8 Mustang when you are trying to merge into traffic, etc. If you are a person that jackrabbits from stop lights, and accelerates toward red lights, only to stomp on the brake at the last minute, you are going to tend to do that with a Mustang, an F-150, or even a C-Max.
Instead, there is a reason you felt the need to post a YouTube video showing how to drive a C-Max to get the best mileage, it requires you to "relearn" how you drive a car to be able to get the best mileage -- and this is true of any hybrid car. Those that don't bother to learn new techniques, like pulse and glide, aren't going to get the great fuel economy. And even people that are willing, many will never have the patience or interest to fully master the techniques.
Now, you sure try to downplay what Wayne Gedes did; you claim they got some great aid from a tailwind but fail to acknowledge they drove in a great deal of bad weather in December -- and that the best temperatures they had tended to be in the 50s, at least after leaving SoCal. In fact, the tailwinds were because of the storms they hit, complete with rain and snow. At best, the tailwinds merely managed to not make the other effects of winter weather not as severe. And if they "did nothing" other than drive slow and have tailwinds, then their 76.6 mpg becomes even more impressive on a cross country trip.
Of course, your first point and your second point contradict each other. You talk about having to "relearn" for each car and, the fact remains, you have learned how to drive a C-Max -- you've had a lot of experience with it. Yet you haven't had that same experience with the Niro, so it is unlikely you'll be able to get the same level of efficiency on a short drive, since you don't know the car. And that is ignoring that, on trips of less than a half hour or so, there are factors such as the state of charge of the battery and engine temperature that can greatly effect the gas mileage; a true comparison would require more than one (or even a few) short drives.
Last, I've had people disagree with your characterization, the the electric motor only assists the ICE (at speeds above about 50, which is what you have said previously). While I don't know that for a fact with the Niro, I've seen others say that it will work at higher speeds. I also have others on the Ioniq that claim it does go into EV at higher speeds, though it is possible -- particularly with the Ioniq having a lower coefficient of drag -- that Hyundai set it up in software differently than Kia did the Niro, despite sharing the powertrain. I know at least one person who is having no issue getting 60 mpg from his Ioniq.
Unfortunately, I seem to be unable to "search" Fuelly reliably right now -- particularly for the Ioniq and Niro, it isn't showing any of the US cars. Even trying to click on ptjones Fuelly banner, it comes up, "There was a problem accessing this vehicle." Fuelly's database appears to be having some type of issue.