The idea that diesel generators will be needed to charge electric construction vehicles, yes, that would be ridiculous, but I doubt necessary in many places. Getting serious juice to most construction sites should be much easier than getting it onto farms, imho, and you even have John Deere building concept very large farm tractors that run off "extension cords" now. Whether or not that actually comes to pass, I don't know, but getting serious juice to construction vehicles, even while they're running, should be a much easier task.
I want to thank all who have commented here.
I'm sticking by my guns, and I'm going to say here that within a decade most CUTs sold new will be battery electric, and
they will be comparable to or less expensive than diesels in price. Plug in hybrids in cars seemed like a good idea a few years ago, but mostly are being bypassed for true EVs now, and I don't expect the plug-in hybrid concept to fly with tractors due to the cost of having an engine generator onboard.
Remember too that the tier 4 emissions have added serious cost to diesels, and that isn't likely to go away. Just look at the Kubota
L2501 for a tractor that is seriously underpowered for its size and weight and likely wouldn't even exist if it weren't for the 26 hp entry into the extra doodads.