I think it's more that nobody has ever tried to order / expressed a wish for 26m vehicles in a six, eight or ten car set, so no technical solution has ever been required. The issue is that as nobody has asked for it before if just a small handful of units had the full cost of developing it it wouldn't be worthwhile.Doesn't work, 80x units must have an odd number of vehicles. Next step up (if even possible) is 11 car.
) still a traditional peak/off peak split, just without the off peak walk up tickets.