They are great for what they are, but I will bet the 400 mile range is not at 75 MPH with the AC on, outfitted as RVs and Campers are. I will bet it is more like 200-300 miles if driven at highway speeds and outfitted with vents, AC, Solar Panels, etc. Charging will take more than an hour if the battery size ( 180 kWh )and stated charge rate (160 kW / h ).
Our use case of our RV is 800 miles in a day, with two refueling / pee break / driver switch stops of 15 minutes and two pee break / driver switch stops of 10 minutes. The extra pee breaks sometimes get extended. Food is self contained, so we don't stop for that. An EV that requires 3 or 4 hour plus stops for refueling won't work for us, even if the price was similar, which it is not.
Now, what they really need to do is to make a small, light EV that is designed to be charged by towing. That would be a fantastic tow vehicle, as the use case for that is to just tool around the local area wherever the RV is parked. Apparently, manufacturers don't support charging while towing, although some third parties have been able to accomplish it. The range would only need to be less than 100 miles. I'd seriously consider that, if it was not too expensive. Of course, then you can usually only go 65 MPH per posted speed limits for vehicles towing.
Regards,
Mark