For me it isn't financial, it's practicality, followed by ethical responsibility. I'm traumatized by a 9mpg supercharged Jeep I drove all around the country for work (the Jeep was sick, the fuel costs, number of fill ups and gluttony of it all really effected me after it was all over). After that, I went diesel and never looked back. My BJ74 has a conservative range of 400 miles between fill ups. I also run biodiesel, which is nice.I hear you, I think it's the future for sure, but it's going to take a while to really take off.
I kind of tell anyone who wants to swap a diesel the same thing, it will probably never "pay-off" You do it because you want a diesel/Electric setup. There are a few cases in which it would make sense, but overall it's more of a want thing.
Even with today's tech, an EV swap makes daily driving a s***ty old Land Cruiser a perfectly viable option. These systems are incredibly reliable. The torture tests we've put the GTe-173 System through (based around the Hyper9) are downright shocking. After you get rid of the ICE motor, you have to worry about brakes and keep gear oil and lubrication in the drivetrain, that's about it. If I had silly money to throw at a Cruiser, I'd grab up an old FJ55 or FJ60 (or even a 70 series), do the upcoming vehicle system and just daily drive the thing without hesitation knowing what I know.