These definitely exist. They are typically referred to as 'compliance cars' - i.e. the manufacturer is obligated, usually by regulations, to produce an EV, but they don't want to spend money designing a new platform for it - so they take an existing model, rip out the engine, cram a motor and batteries wherever they will fit and call it good. Examples: Volkswagen eGolf, Fiat 500e, Mercedes B Class EV. Ford Focus Electric...
However, doing this means you are constrained to the shape of the combustion vehicle it is based on. So the aerodynamics may not be optimal to get the best range, you may have a transmission tunnel taking up space in the interior that is no longer necessary, directly swapping the position of the engine and the motor/inverter means you lose the opportunity to repurpose the front of the car for additional storage - ultimately it ends up compromised in one way or another.
If on the other hand you design the platform from the ground up to handle an electric drivetrain then all of these points can be taken into account.
(And regarding cars in general becoming rolling computers: this is not an EV specific issue, unfortunately.)
I think the key issue here is that, regardless of generation, most humans are stupid and impressionable.