There will be a viable market for EVs. Just not all/every vehicle or every person. Not nearly everyone in the next few decades. For power in vs. power out, electric motors are very efficient. In terms of $ cost for that power, that is another matter which will vary quite a bit over time. Question will be how much of the overall market.
Personally there is no way I would wait 30 mins to charge (assuming an available charging station) on a road trip. What happens if you get to where you must charge up but there 5 charging stations and 20 cars in front of you? I think you will find yourself putting a small generator in your car so you can buy gas and charge your car just in case. I think the idea of a hybrid or add on combustion engine is the backup source of electricity is likely.
An EV as a second vehicle for a regular home to work to home commute....that could make economic sense. Or Delivery vehicles, buses, or other vehicles that drive a routine route and have natural, regular down time for charging. Especially if it is cost efficient for a municipality or a business.
GM's announcement to be all EV is probably just a gimmick to get some activist investor funds off their back. Later when "market conditions have changed" they will back off that commitment. Otherwise they will be ceding a chunk of the market.