A well-written article, I thought. However, my take on it is simple:
In 2003, I owned alongside a couple of others, a 1990 Golf GTi 8v 5 door. A practical, compact, reasonably quick car with no catalytic convertor, no airbags (but still considered a safe car by 1984 standards, when it was released). It returned a consistent 44mpg, returning 52mpg on one 20 mile run where I drove to get the best returns. I ran it on Shell Optimax, since the knock-sensor equipped GTi was designed in an era of choice between leaded and unleaded and would happily use the higher octane fuel.
In 2004, I got a VW Beetle Cabriolet. A 1.6i model, it did 30mpg. I considered this dreadful for the size of car.
However, look at the new car costs as well as weight. The 1990 Golf GTi Cabriolet, a 1.8, fuel injected compact convertible cost £13,995. The 2004 Beetle equivalent cost £15,495, despite inflation, increases in earnings, housing costs, the supposed "environmental concerns" of car ownership, and much, much more material used and equipment provided.
How can the car manufacturers possibly hope to innovate? They are charging a relative pittance for their products. The 1990s saw a mini-Malaise era for Europe, with astoundingly directionless designs (the original Renault Laguna, the 1988 Passat, Saab's 900/9-3) and some truly awful cars. Cars like the Honda Jazz and Mercedes A-Class, offering real innovation in the marketplace, are naturally quite expensive.
However, for 2003 driving conditions, my little Golf was perfect. The reasons to not keep on driving it were largely based around it being a 14 year old CAR, not a 19 year old DESIGN. If I could have bought a brand new one, I would have done (not counting the CIti Golf).
To save the planet from car users, we need to:
Make new cars considerably more expensive, either via taxation or natural market forces (pay the workers what they need, accept that shipping cars for a US market from a US marque from Korea should not be required when that US marque is laying off workers in US plants - the same theory as "food movement" applies; environmentally it is better to make products for local consumption locally and cut out that stage of travel and energy consumption).
Change working habits. Work from home or provide smaller, local offices.
Provide viable alternatives. I know the US is even worse than the UK for public transport; Europe and Eastern Europe often show genuinely workable alternatives.
Accept that cars are dangerous. Stop making the body in white twice as heavy to try and save the occupants if they screw up. Train drivers correctly, accept that sometimes car driving will cause death, and make the cars smaller, more efficient and space-efficient.
These aren't magical fixes, but I think that making new cars more expensive would have a knock-on effect of increasing used-car values, and making maintaining used cars viable. For many US/Canadian readers, for whom the social norm would be to find cars up to 7 years old utterly respectable, and in the latter case may indeed have financed their new car over that period, the attitude of British car owners would probably be horrifying.
Oh, and if you can, drive a Japanese import. IMO, the decision to drive a perfectly good (often far, far better than a UK example of the same sort of car at the same age) car which is deemed almost worthless in Japan is very environmentally friendly, despite the shipping to the UK. It means that the car will almost certainly last another 5-10 years if correctly maintained, rather than perhaps being scrapped in a year or two in Japan.