The Bolt won't be a game changer - or a "big step." In fact, it's a pretty awkward product - too little car for too much price, a slightly more attractive, more practical Nissan Leaf. 200 miles may look good compared to older EVs, but it's still way too low, before we even talk about the underdeveloped charging network, lengthy charging times - and bad timing, as per this thread. Even the debut was a yawn - it debuted at the Consumer Electronics Show and still managed to be one of the least interesting cars there. Pretty far down the list at the Detroit auto show, too.
Chevy can't even move the Volt, a more practical all-around car that's an established name and is now like $25K after rebate. How can you expect it to make big strides with a $30K all-electric Bolt?
Expect it to take 350+ miles or so, a more universal charging network, sub 10-minute charging times (without any of the ...80 percent full crap), and a more practical car with pricing semi-competitive with its gas equivalents before we even start daydreaming about a "game changer." Then we can wait for a whole market of similar cars before "mass adoption" is a term worth bringing up. Our best-selling car is still a pickup truck.
Plug-ins as a whole (which includes plug-in hybrids as well as EVs) made up less than 1 percent of 2015 US car deliveries, and 1 percent is considered good. If people were anywhere near as eager to embrace EV tech as you suggest, they'd have been eating up plug-in hybrids for at least the past two or three years. They offer a great alternative right now, giving you everyday electric driving, excellent fuel economy, no range anxiety, decent sticker prices, and a car you can drive straight across the country if you want. Yet we're not interested. I'd put that 15-year projection right back in the vault if I were you.
If you want a more interesting car that could be a stop on the way to a game changer, forget Chevy and look over the Atlantic at VW, most notably the Audi e-tron quattro. Just a concept, but it'll be launching in a couple years and VW has it at 310 miles. That's a range that'll start to turn heads, especially in a legitimately packaged AWD crossover. That's assuming the production car carries the number and design over, a big assumption considering what VW has on its plate now.