This is a big concern for the used market, too. FWIW, I bought my Volt from a dealer who had used it as a quasi company car (I was told one person mainly used it). Its average MPG when I bought it was only about 60 so it was rarely getting charged.

In the UK it's been noted that an overwhelming number of PHEV owners never charge their battery. If anything it shows that, even with a more accessible stopgap people are more willing to buy, the actual problem is changing old habits. An EV forces that. A PHEV does not. People don't like force.