We had similar here with LPG when I was younger. Guys paid thousands of dollars to have their car converted, so it could run on this waste product, nice and cheap. The government even subsidised the conversions for a while.
Then the taxes came. Now there's literally zero advantage in having a vehicle converted (losing half the vehicle's boot (trunk) space.)
its infuriating...
Only if you're one of the handful actually paying attention. At least it's not so lonely any more :)