This probably has little to do with maintaining roads, fairness , etc. It has more to do with finding a new revenue source to take advantage of. Sort of like Douce Bank saying that Work from Home people should pay a WFH Tax.
The most enthusiastic proponent of an EV tax has been the Infrastructure Partnerships Australia
https://en.wikipedia.org/wiki/Infrastructure_Partnerships_Au...
Infrastructure Partnerships Australia is an independent think tank that looks for ways to raise capital. To justify their existence, they look for ways to separate the masses from their money. Just another private group run by Corporate hacks and sleazy Gov.
ICE Vehicles pay registration fees and a gas tax that's suppose to go into the Road Infra but never entirely does. EV's pay registration fees and I'm sure there is already a tax on electricity that is used to charge them just like there is a gas tax for ICE Vehicles. So isn't this double taxation?
Perhaps the problem here is you could get a few Solar Panels and a Battery/Storage device and deny them their revenue/profit/tax. We can't have that, can we....
As soon as technology starts digging into the pockets of Tax Revenue, a new Tax comes along to negate any savings benefit for the consumer.