As someone who does engine calibration for an OEM I can tell you that with drive-by-wire there are many, many more maps, parameters, emissions controls, etc. that come in to play for an ICE. For a purely electric vehicle there's not any of that so there's no reason there would or should be a delay. The only change I could see there being would be for different driving modes which would basically just change your torque multiplier to deliver more or less torque per degree of foot rotation.

Drive-by-wire allows for an extreme level of engine control and fine tuning that isn't present with cable throttle, including over things like emissions, which is why the car doesn't always respond right away. In today's day and age the driver doesn't always get what the driver wants if cars are to meet all the emissions, performance, and safety standards required of them. Delay with DBW is far more of an issue in AT-vehicles than vehicles with an MT or DCT just by nature of how the transmissions work. It's not necessarily that OEMs are trying to dull down pedal response, they're trying to make sure the vehicles have exceptional drivability which includes but is not limited to no clunks, bumps, surging, etc. and also smooth and quick response. With an AT - especially the newer ones with many gears - you almost always get shifts and so torque and other parameters need to be controlled to ensure smooth shifting and hardware longevity.