Maybe some day GM will have a CCS or Chademo network that rivals Tesla's supercharger network. But until then, any other EV is really just a second vehicle.
Few people drive all the way across the country. Rather, they make long distance trips to vacation or visit relatives within maybe a 500 mile or 1,000 mile range.
A Bolt EV driver could drive from San Diego to Vancouver, Canada immediately after picking up their car from a dealer 2 months from now. The section of the trip from Sacramento to Oregon would currently need to rely on 24 kW (62A) charging. However, within the next 2 years an additional 41 DC charging locations in California with 50 kW (125A) will be built with funds already granted including along that northern stretch of I-5. Those new charging locations will also include stubbed-out locations where a 100 kW (200A) can easily be added in the future and the site transformer is already sized to account for it.
Similar DC charging opportunities exist along the east coast today for long-distance driving.
However, the bigger picture you raise is about a nationwide Supercharger-like network for car owners between the coastal areas. These areas of the country, in addition to the coastal areas, are likely to see a major initial DC charging buildout with 100 kW (200A) or better CCS/CHAdeMO for long-distance driving by the end of 2019 with future installations continuing after that.
The buildout will likely be done by VW using $500 million during that timeframe which is probably more than Tesla has spent on the US Superchargers so far. VW has to spend this money on zero emission vehicle charging and while this could include fuel cell H2 charging it can be entirely EV charging. VW gets to choose and VW is not one of the car companies with a major stake in pushing fuel cell cars today. Rather, they are planning to produce large numbers of EVs with long-range big battery cars being delivered within the 2019 timeframe.
Yes, this nationwide DC buildout is my personal speculation. They could spend this money on other zero emission technologies or just on workplace and apartment building level 2 AC charging stations. However, it's hard to imagine them not doing a national DC network given VW's stated near-term EV business plan and the scale of the funds involved.
This investment is mandated under a court-supervised consent decree. They have to do it. The first of four consecutive installments begins in spring of 2017 and ends in late 2019. If they fail to spend all of that money the remainder can be rolled over to the next 2.5 year installment of $500 million but if they haven't spent $1 billion on charging by the summer of 2022 they will face fines. VW picks their own investment plan but it is supervised by EPA and CARB and the kind of costs that can come from the fund is clearly limited and is audited and periodic public reports on progress and upcoming plans are required.
Change (and charging) is coming quickly across the US due to this settlement although it will likely follow a roadmap rather than being equally distributed across the country every year (the same is true of Tesla's charging strategy). Although this work must benefit all EV models using "non-proprietary" plug designs (not just VW) it can (and likely will) dovetail with VW's need for a nationwide high-speed DC charging system since VW gets to choose what and where to install this charging network. I know it's hard for people to wrap their heads around what this settlement means....
I'm actually sitting in the US courtroom where the final settlement hearing is taking place today.