Good point. Natural gas engine would be a great practical step forward, especially since the big diesel engineering shops already develop and manufacture natural gas engines.
If it weren't for natural gas we would still have massive coal fired power plants.
If you look at UK emissions which have been declining steadily since the 1990s, this has been in no small part due to the move to natural gas.
While it would be great to move to carbon neutral immediately, we can't do that without driving up energy prices massively and causing widespread poverty and disruption, so there is definitely room for some middle ground compromises.