V2V to help out a stranded EV is more than a "nice to have
Personally I'm not in the market for the addition cost to the vehicle and R&D etc. for that blue moon occurrence, and even if I had it I wouldn't be that thrilled sat there transferring juice. Not quite the same as having a gallon of Petrol in the boot!. I think much better that e.g. AA has vehicles with battery packs that can do that (I have seen those in USA). Or perhaps just enable towing the vehicles in Neutral? Just need to rope in the boot then

(YouTubes available of people being towed to get a charge ... fairly sure that isn't in the manual!)
the other factor is the length of time the AA guy would have to hang around to do the charge during which he cannot be helping others.
Do they fix stuff road-side these days? I have no idea, but last time I looked under the bonnet on an ICE and all I could get to was the Dip Stick! Old-pair-of-tights instead of fan belt didn't look like an option
If, in practice, they have to flatbed/tow most of the breakdowns then I don't suppose flat-battery will waste any more of their time, and much lower incidence of mechanical failure of EVs might threaten the vehicle-recovery busies model anyway? Only need to move the car to the nearest charger - whereas for a breakdown its going to be recovery to home location I guess.
Has anyone run out of gas
IMHO its quite hard to do (well, in a Tesla, other cars don't have useful info about range on dashboard [
James and Kate YouTube on MG ZS Range, particularly the bit at 7:00, had very different on screen info compared to actual - Daft idea].). The Tesla TRIP graph shows you predicted arrival SOC%, and then an actual line and revised prediction, so when that drops very low you have earliest possible warning to do something about it (slow down, or plan an additional refuelling stop).
First example random-pick from Google ... driver is doing considerably better than (grey) prediction

, perhaps slowed down.
I have had one touch-and-go journey where I left at 90% and arrived at 50% having left late and driven like the wind, I thought nothing of it as no rush on return leg so 50% should have been fine. Return, Summer day, was torrential thunderstorm and even driving at 50 MPH I got home with 1% - but from the info in the car I knew early one that the journey was going to be trouble; it was only because it happened early in my ownership that I didn't immediately recognise the significance, and way back then far fewer charging opportunities - I would have needed RFID or membership with funds-on-account already set up for pretty much any 3rd party charge that I might have been available ... back then.