I think it has 70% to do with image, and the rest split between price and education.
Consumers in countries like the UK and US buy with their eyes, not their brains. if you make something look good, it does well. Very hard to understand why the PHEV was a runaway success, and the IMIEV not, with the majority of UK PHEV sales being in London to take advantage of tax breaks, the I is unquestionably the better car for london, but the consumer likes the SUV... it's just fashion.
The vast majority of people are neither technically minded, nor particularly utilitarian.
Most simply go to the dealer run and choose the best looking car that fits their parameters with the easiest to budget finance deal. Since Mitsubishi neither have that many dealers compared to the other big names, nor pushed finance options proprely, it cost them.
Their Cabled trial, which can be easily researched was about the total of their marketing, so their approach to market was too academic, and didn't make the mainstream. Dare I say you need to advertise on prime time TV shows, something they understood with the PHEV and got right.
Some manufacturers can sell total junk, but because it looks pretty, they still sell.
I don't think the majority of people recognise that in a city like London, 70 miles is more than enough, nor have they assessed their needs. Most people have busy lives, just need any car, and can't yet be bothered with the charging faff that comes with a BEV, and they don't understand how to basic plan their journeys around a 6 hour charge... so in essence they are actually lazy, or lazy by proxy. So, they just continue with what they know.
Dare I say I think the Scandinavians, French and Germans are more utilitarian, and less image focused in the main, hence better uptake.
I've noticed a slight price increase in UK prices, perhaps 10% on used values, but they remain low.
I don't think Mitsubishi are sitting on a gold mine, no... the body on the I is aged now... 10 year old design, style has moved on, and they have missed the boat with this model as range has progressed too... so it will remain a classic in the EV world, but it won't be reintroduced now, as Nissan will go with their better sellers.
Last issue was that the IMIEV served as a great city car, but also as a second car really, requiring an ICE back-up. nowadays, I really think for market penetration, you want a Leaf sized car with about 130 mile range. I would not buy the I as a sole car, it can only be a 2nd one.... it's a problem that most people would arrive at.... and in a city, many only have space for 1 car... bit of a catch 22.
2012 I-MIEV Keiko Silver 16K
2010 Insight ES-T 43K
2001 Accord Type-V (F23 manual)
2009 Hornet CB600F