I own an EV (in Ireland). I would not say by any stretch I save that much as running a petrol car. It's probably in the order of a third perhaps and that's with a nighttime electricity plan where a kWh might cost 20c which works out about €4 at 15kWh/100km. A petrol car doing 6L/100km would cost about €12 at the moment. If somebody was using public fast chargers they would see very little savings.

There are other expenses like motor taxes, wear & tear (tyres, brakes), servicing, oil changes etc. which might affect the cost. The UK also has a really dumb excise on EVs where they get whalloped with 3p per mile of extra tax. So 100km (62.5miles) is £1.87 of tax to add onto the charge bill. Luckily Ireland doesn't get it but most other expenses are comparable.