Battery energy density is improving at about 7% per year. (http://www.greencarreports.com/news/1074183_how-much-and-how...). After 10 years, that's a 97% improvement. If one of the new battery technologies becomes feasible with all of the new investment in battery research, there could be a much bigger jump in energy density before then.
That's not really what the attached article says. That article says that (1) nobody has any reliable data; (2) the general trend is assumed to be down; (3) the order of magnitude of the current data variance is 10x the "guestimate" of the future growth rate. Not sure this is the type of data you want to extrapolate from.
Range isn't going to get magically solved. A Macbook Air gets amazing battery life because of advances in getting more computing with fewer electrons, not because batteries are all that much better. In contrast, the energy required to push a car down the road isn't going to be reduced by orders of magnitude. So it's up to battery tech, which has been slow to advance.
We'll see what happens with the charging infrastructure. Blink seems to having a hard time making a go of it, and their rates are pushing up against the cost of gasoline if one charges at the mall.
I know of no reason for battery prices to fall. Maybe they will, but I wouldn't stake my reputation on it.
Yes, electric cars are simple and require little maintenance. You know what else require little maintenance? My 2005 Scion xB. Tires, oil, and filters in 70K miles. The Leaf doesn't need oil and most filters, but to me those two things are trivial. If the Scion is typical of most Toyotas, by the time the Scion needs an engine rebuild, we'll have probably replaced the battery pack in the Leaf at least once.
I love our Leaf, and I'd buy another one (or a Tesla). But to describe EVs as an inevitable future is to ignore or wish away the current limitations.