Tbh, I'd be happy if it did. Half the reason motorways are so dangerous are the massive differences in speeds and people not expecting them. Granted, that's down to observation rather than the actual speeds themselves, but even so it honestly wouldn't bother me if they did do that. Managed motorways flow better than non-managed ones, albeit slower for those that are happy putting their foot down, so ultimately it could actually benefit the movement of people.
It's a short-sighted view I know, as it's not a huge leap from there to doing the same thing on the fun roads too, but I suspect that's a whole new level of cost. Haydn's right though, the tech cannot support that right now, although it won't be that long before it can.