Personally I believe for the average consumer, an EV versus CNG will be the preferred solution and will win out over time. For larger trucks and transport, CNG initially has interesting attraction and I do have money bet on that solution.
Also though, this is a BIG part of why I like TSLA. For GM they have to outwit the "Innovators Dilemma". That is a big hurdle to cross!! TSLA DOES NOT have that problem, they have one focus and no internal confusion or conflicts on the horse they are riding, and need to nurture to the finish line.