I'm not exactly sure the shortcomings of the law that you have described are actually shortcomings, for the following reasons:
1) Yes, van with older tires should keep larger distance - this is lawful and ethical thing to do. Just because it's a van, heavy vehicle , with, well, older tires. Thus it has longer stopping distance. The fact that drivers of such vehicles (or any vehicle for that matter) usually do not want to realise.
2) I'm not sure which country you live in, but I have a feeling that in any country getting insurance payments is hard enough that you would be willing to search for a buyer for your vehicle instead. And that's not to mention that you may be injured in such collision, more than you think, especially if you goal is to 'total' the vehicle. So, no person in their right mind would attempt this.
3) Probably most importantly. If you hit the brakes and someone hits you from behind - yes, they were following to closely. This is by the definition. And following to closely (and hitting someone as the result) is against the law. You might have done something ethically wrong by hitting the brakes for no reason and there is no law to punish you - that is true. But the other side did something ethically wrong and unlawful - and got punished. That is what law was intended to do.
So I guess my point is that yes, law is not perfect. And yes, you can quickly change lanes and brake in front of somebody not giving them opportunity to get back far enough. But I would argue that current law is the best that we can get with currently deployed technology.
Is better law possible? Probably, with onboard recorders, dash cameras and stuff, mandated by the law - better law would be possible. But I can only imagine the amount of whining about 'privacy' from people why think that are entitled to drive +20-30km/h over the speed limit.
All in all - current law is probably the best possible in current situation. Which means that we, as a society should do our best to obey it. And not to blame the guy who was stopping for red light/squirrel/kitten or child on the road.