CNG fueled vehicles have been around for a long time. In Texas many companies were utilizing CNG fueled fleets back in the 60’s and are still going strong.
Technology has improved greatly in the past 10 years and CNG refueling stations are popping up everywhere in Texas and Oklahoma. Oklahoma is providing many incentives to either convert or purchase factory equipped cars and trucks.
BTW....little or no difference in fuel economy.
I wasn't aware of a great increase in the tech; though I do remember seeing/using/fueling some GSA Diesel/CNG pickups (they could use either), I never got to see/use the CNG functionality as we only had Diesel at the fuel-point.