One of the key points in the article is that the emissions regulations effectively force the manufacturers to build the wrong cars. The official test methods need to be more effective at regulating the emissions produced over the full operating range of the engine.
The downside of that is likely to be a hit on performance and an increase in costs as the aftertreatment systems will need to have more processing capacity, which most of the time (like engine power) won't be needed in real driving.
Another key point (and one that I've espoused for years), is that so-called zero emissions vehicles make particulates from tyre and brake pad wear.