The current VED regime is a bit of a mystery to me, to be honest. Way back, it was on engine size - under or over 1500cc. OK, something of a blunt instrument, but I think we could all see what was what.
Then it was based on CO2 emissions pr mile (which is what I think helped incentivise a lot of people towards diesel). Again, I could see the sense in that.
Then it went completely bananas and we ended up with the current scheme, where only the first year's tax is based on CO2 emissions,and after that you go on to a flat rate, almost regardless how much CO2 your vehicle emits, (unless it's electric). On top of that, you have a hefty extra chunk of tax to pay for the first 5 years only, if the list price was over £40k. As far as I can see, this seems to incentivise the use of older gas guzzlers above anything else, which seems utterly crazy!
And then from 2025, yes, EVs will get hit too, because, not content with incentivising over-5 year-old gas guzzlers, they want to deincentivise low CO2 emissons vehicles.
Hopefully, we'll have a different government by then, though...