Remind me - how do Internal Combustion Engine cars (ie petrol, LPG, diesel... ) subsidise EV today?
1. Purchase taxes eg the £3K grant for EVs: EVs still pay VAT, so the EV grant is just an extra layer of bureaucracy (they could have just cancelled VAT for EV instead). The EV grant exceeds VAT only once you get above £15K pa (good luck finding a worthwhile EV for £15K). So no subsidy there.
2. Road tax: EVs < £40K don't pay road taxes. But other vehicles pay more into general taxation than gets spent on roads! eg £6.5Bn raised by VED vs £4.8Bn spent on roads?
3. Numbers of EVs today are low: the UK govt says 0.5% are "ULEV". So of the 38.4M licensed vehicles (March 2019), that makes ~192K EVs (2019; 160K in 2018)... so EVs are being subsidised at £125 pa per electric vehicle. Or each non-EV is subsidising the EV's contribution to road maintenance at a rate of 62p pa. So basically nothing.
SO may I respectfully suggest petrol car operators and owners subsidise lots of things (especially with fuel taxes), but EV subsidies are pretty low on the list (and at least this something car-related being subsidised rather than the usual car-as-a-victim).
All numbers trolled from the interweb and subject to errors etc
