Yeah, Model Y probably should have come first, but I think many people forget how long ago that decision was baked in. It's in the *original master plan* from when the *Roadster* was released. They were working on "Bluestar" all along. For most of that period, sedans were dominant and station wagons ("SUVs") were a smaller, niche market. I think Model 3 was much too far along in development and they were not ready to change the form factor by the time the shift from sedans back to station wagons (under the new nickname "SUVs") happened.
I think back in the Model 3 design phase, Tesla needed to be very much aware of the public's propensity for range anxiety.
So it would be natural to bring the most efficient car to market first.
Like it was done with the Model S, which was followed by the X.