I did not read all post in this monster thread, but to the question (if it is true) the Nissan Leaf is PURE EV... which has advantages of simplicity, no transmission (well single speed planetary). It has NO engine, oil, filter, transmission... etc. That is why.
The VOLT (serial plug-in hybrid) is actually like the Prius (parallel plug-in hybrid)... has clear advantage over the LEAF, i.e., RANGE... However they are complex and still have the care and feeding of a regular car.
Market rules. For me I can't afford (practically and fiscally responsibly) a new Tesla. To me the LEAF is the poor man's Tesla. Do I need more range. 2 or 3 times a year I need to do +80 miles round trip to a neighboring town (a few towns over).... The LEAF at least mine is pushed to do that on single charge. There is free charging (if the spot is open???) at a hotel in that small town. Assuming I can plug in, I can have lunch while I give it a hour charge, to give me the buffer I get home easily. So even if I had 150 or 200 mile range I wound not use it that much. I still have my Diesel VW TDI JSW.... I keep it for that reason, to go cross country (I mean 700 miles on one tank at 50 mpg).
Sadly figuring out how fast my battery is going, cost to replace the battery, my EV is going to cost me twice what the fuel bill would be for my VW TDI (not including the oil changes, but I do that myself). I have dipped my toes in the EV pool. I see it and like it, but I am not giving up on my ICE Diesel. If I had to pick ONE for the rest of my life... IT WOULD NOT BE A PURE EV.... It does not work 100%. However I often thought IF I DID GO 100% EV... for the times I need to go further I have my BMW motorcycle or I can RENT A CAR...