I think they'll end up pricing themselves off the road. The tide is already turning with so many more smaller cars. Unfortunatly I live near the 4x4 capital of Australia (Chappel Hill, Kenmore and Brookfield/Pinjarra Hills).
Take this for example. I drive dump trucks at work occasionally and I'm supposed to get a ticket for that (lol but I don't). Theyre much the same as a car, with two axels and an automatic gearbox just theyre much much bigger. I'm sure a soccer mum could get in one and drive even if its a bit daunting. I'm also sure she'd smash into stuff and probably roll it over. Is a 4x4 all that much different.
I understand that the majority are being punished because of a minority who can't drive for shit (although its probably the other way round). Aviation is no different. I have to get an AVID or an ASIC because a couple of dumb f@$ks flew a couple of planes into a couple of buildings *grumble*. Now I'm not happy about it, but thats what I have to do to get my licence so thats what I do. If you were a keen 4x4 enthusiast, I'm sure youd be pissed about it, but you'd get over it and move on.
You could also see it as a "green" solution. Its more difficult to buy a 4x4 than just buying the thing, now you have to get a licence. So sales drop and theres less greenhouse emissions but I guess the large familys will still buy 4x4s or MPVs.
Rob: I understand that your a 4x4 driver and you don't like the idea, but until you drive around kenmore in a celica whos roof line doesnt even make it up to their windows you wont understand just how scary it is. Licences might not fix this, but it should help weed out the soccer mums who couldnt drive for shit in the first place.