I think everyone worries about the hypothetical long distance "emergency mission". The most likely one for me, will be something going wrong with my elderly parents, 150 miles away. That's well within my 200 mile real range, so happy days, just pop down there. The next thing will be "Ah, but what if you've just come back from a 180 mile trip AND THEN something goes wrong with your parents"? (Well, the honest answer to that, is that I'd grab my wife's car keys and use her car)! But then you get the "What if you've just come back from a 180 mile trip and something goes wrong with your parents and your wife is out"? And in that situation, yes, I'd have to visit a fast charger on the way and yes, it would add about another 20 minutes to a 150 mile trip.
But it's interesting that you have to get down to that sort of level of unlikeliness! Nobody would ever dream of applying that kind of contrived scenario to an ICE situation!
Since I've had the car, the only actual, unforeseen event was when the lad had to go back to university after Christmas, and the trains were on strike, so I had to take him. He's a good 250 miles away in Leicester, so there was no question of getting there on one charge. It meant I had to stop for a short break to charge - which I would have done anyway, on a trip that long. I could have stopped for about 10-15 minutes on a fast charger, but we actually stopped for 45 minutes while we had some lunch, so that reduced the amount of time I had to spend charging on the way back. It really wasn't a big deal.
But as for the other problems, yes, there are electric MPVs that probably have that much boot space. And yes, they are still way too expensive. Part of the reason for that, however, is because everyone is putting off buying an EV because they don't have an 800 mile range, so there are very few second hand ones and they haven't filtered down to the £800 mark, yet. But of course, that's very much a chicken-and-egg situation! The problem is that if we all keep waiting for "the future", there may not actually be one...