Something tells me that the used market for a tesla isn't going to be as strong as for a honda civic
Not sure why you'd assume that.
Current Tesla models have excellent residual values: 62% at 3 years according to black book, which is excellent for the luxury segment - and even better when you consider that EV values tend to be skewed by tax credits!
The Model 3 will share features like over-the-air updates that should help it retain value well.