The only issue as I see it with self-charging hybrids is that all the electric motive power still comes from burning the fossil fuel in the car. For folks who regularly need to do long distances the PHEV is a much better option in my view as you can still charge from your solar array if you have one and for local running around you'd be doing it nearly all on electric.
I take your point - and would add that experience in my short-range PHEV shows that they can recover useful charge while on the move. For example, a mostly motorway 120 mile commute would see the i8's notional 34 mile battery range would be making a contribution for the first 100 miles or so.
I averaged about 49mpg for typical UK motorway driving - so that'll be a mix of 65mph in 3 or 4 busy lanes, stop start 0-5mph around Heathrow, and 70.0mph on the wide open plains for the M40.
The reason I'd not try that journey in an EV - where I often did the return trip in a day, or with an overnight stay - is that I couldn't guarantee that the plentiful chargers in the company car park would work (about a 50% strike rate to find one that charged).
Will