No.
Someone in a position financially able to buy a new car should not be subsidised in that purchase. That subsidy will inevitably come from the pockets of those who cannot afford to buy new. Morally wrong and further fuel for those who would prefer to see the whole carbon reduction project skewered.
Selling advice I was given: Sell benefits. If you cannot sell your product at a price the customer regards as good value then the product is in some way flawed.
I have to disagree, on two counts.
Firstly, as has been pointed-out on this thread before, a reduction in the price of new vehicles leads to an immediate reduction of the price of second-hand vehicles. If, say, Tesla dropped the price for their Model-Y by £20,000 tomorrow, then all second-hand Model-Y cars on dealers' fourscores and on Autotrader will also go down in price on the same day (though obviously not by the full £20,000), and any current owners of a Model-Y will have to adjust their expectation in respect of their cars' value. This is why a subsidy for new EV will benefit all EV buyers, old or new alike (though obviously not by the same amount). You could argue that people who do not own cars should not be participating in
any subsidies given to
any type of private motoring, but this is a different issue.
Then, a common argument against the government incentivising EV ownership is that the CO2 reduction attempts are pointless (because humans don't affect the planet's temperature, and/or because EVs do not produce less CO2 overall, and/or because nothing that we'll do in the UK will make any difference anyway because of America/China/India etc, and/or that saving the planet is important but not at an excessively high cost to the current generation, etc).
However, the CO2 argument ignores the totally-separate air quality issue. And the arguments here are much weaker (that when EU7 is introduced the toxic fumes will be minimal, and/or that there's no evidence that breathing car exhaust fumes causes health issues, that the cost for 'clean air' is too high, etc).
Regarding the air-quality issue, I do not personally think that using public money to incentivise the uptake of zero-exhaust-emissions vehicles for cleaner air in urban areas is unjustifiable. And, it benefits everyone.