We have had LNG/CNG for forty years. There have been huge fleets of public sector vehicles converted to it in the past but those vehicles were not replaced with more LNG/CNG vehicles. There was also a considerable tax incentive.
It was a failed experiment. It never took off. Already electric cars have better infrastructure and higher uptake and it isn't as if governments are fleet buying electric vehicles for councils/utilities to use. They had been doing that with the LNG/CNG things several decades ago, and building some refilling infrastructure in depots.
When you compare the success of diesel in the European market for small cars you can see a change of fuel is possible. Diesel isn't as cheap as it once was but it still commands a large part of the European market.
I think we need to look to China and what they are doing. It is full steam ahead for electric. The diesel and petrol cars will simply get replaced with new vehicles, there won't be any conversion to LNG/CNG.
We get the full Musk vision of robot taxi cars that do their fleet thing removing the need for car parks and making roads safe to even the lamest squirrel, but the real danger to the automotive status quo is affordable Chinese electric cars that pass the safety tests and are nice to be in just because they are electric. We have had the market changed before with Volkswagen and the Japanese cars coming along and actually being what people wanted, despite being alien to the established industry.
Most cars you see reviewed are refreshes of the existing conventional ICE models, they have updated styling and updated infotainment systems with a revised version of the same platform. Despite the failings, Tesla are 7 years ahead in redefining the automobile product. The incumbents are not really trying, they are just running these ICE refresh vehicles. The market isn't going to be disrupted by them.
Meanwhile, in China they have 5 and 10 year plans to dominate the automotive trade with fully electric cars. Plus the incentives in their domestic market make things possible at scale. Much like how the VW came along with a better value proposition the same can happen with Chinese electric cars. If the payments are easy and the warranty lasts forever with the running costs much lower than ICE then the market for second hand ICE cars will be reduced to scrap value. As soon as it comes to replacing a part such as a bolt buried deep in the transmission somewhere it becomes more sensible to scrap the thing.