The Model 3 has also been simplified with service costs in mind: no Falcon Wing Doors, no complex self-presenting door handles, no sunroof, using easier to cool PM motors, using a re-designed battery pack, etc. etc - and the cherry on top is a very clever minimalist interior design that also happens to reduce manufacturing and servicing costs and increases vehicle life time. Car interiors tend to age the fastest.
I believe in a few decades the Model 3 will be taught in business school as an example of modern manufacturing breakthroughs.
So yes, certain versions of the Model S had service cost problems, but that was not really an inherent property of the EV concept, it was more like a side effect of the aggressive innovation cycle and learning curve Tesla went through as a newcomer to the automotive industry.
Note that early Model 3 batches obviously have a higher chance of being more service intense, and there's inevitably going to be recalls - but with the Model 3 I think we are going to see the first high-volume demonstration of how good EVs really are, in terms of significantly reduced service costs.