Well, apart from the issue of all our cars having the steering wheels on the wrong side, there's no inherent difference between driving on right and left, it's all based on the days when chaps carried swords anyway. So in those terms, I wouldn't be that bothered.
And right hand drive cars can be driven on the continent, so it's not impossible, it would just take more thought and care - god knows, some people seem to need an extra reason to be careful, maybe that would do it.
I was thinking a while back, actually, that perhaps one reason some people don't leave enough room when passing is that they are sitting on the far side of the car from a cyclist, so to them, the gap between 'them' and the cyclist is 'whatever space they leave PLUS the width of the passenger seat'. Perhaps if the driver was on the kerb side, they might be more aware of how close they get...?