I don't know if it's been mentioned but Italy and most of Europe base a car on several specs. Engine size and the lack of a trunk according to James May. For some reason unknown to me or Jame May England adopted the three wheel rule and former colonies seem to have fallen in line. I guess it's similar to the kei cars in Japan but even less regulated.
The interesting thing no one has mentioned is the new low volume laws that are fluctuating. They are designed to make kit cars and replicas easier to sell but I don't see why Elio couldn't use it. The amount would be a problem at first but 325 is better than zero. Well, maybe not.
As for the cost of ownership, it depends on the country when in Europe. I do think this, owning a car there costs way more than here. I checked out my Golf and the cost of owning it in Germany per year (taxes and inspection). In the US, my car costs $35/year for taxes (aka license) and $75/year on inspection/emissions. The same exact car in Germany would be $550/year in taxes (aka license) and $600/year inspection/emissions. If I had a diesel the taxes would be $400/year (inspection and emissions are the same) and $350 if I had the 998 cc 3 cylinder turbo motor in it. As for the US, it doesn't matter what I own, they are the same for taxes and the only savings is a diesel because where i live, no emissions.
One of the reasons why a VW Golf is the biggest seller for VW in Europe is because it checks all of the boxes and it's not some micro car that is impractical for everyday use. So, this is why no matter where you go in Europe, a 4 door hatchback with either a 1599 cc diesel or 999 cc 3 cylinder are the biggest sellers. Those are the tax breaks. Since Europeans are not too hip on owning more than one car, they get one that counts. The biggest problem that kills the microcars is public transportation. It's too easy and too cheap to use. No need for that microcar, thus the reason why you rarely see them any more as opposed to 30 years ago.
As for those Kei cars. They are going away too. They were all the rage back in the 80's but now you rarely see them. Just like in Europe, people but one car that counts and then uses public transportation.
If we taxed cars on the fuel consumption, emissions and engine size like in Europe, we'd see a completely different landscape. The Elio would have been out 10 years ago. In the end, Owning a Suburban vs a Nissan Versa costs the same per year. As for an Elio not enough to make a difference as it's only $19/year on taxes and $20/year for inspection (at least where I live). $39 vs $110 is not going to make someone sell that Surburban. If it was $1,500 vs $30 then that might get people thinking.