I think:
* Roadster is just sporty for a driver and passenger, and even owners report trouble getting in and out as drivers.
* Model S is just for two adults in front and two very small people (children or adults) in middle row, and small children in back with optional rear facing seats. Model S is relatively easy to get in and out of in front seats.
* Model X is for two normal sized adults in front, two smaller sized adults in middle row or three not-large children (perfect for growing family), and one slight adult and one to two not-large children in rear, possibly one full sized adult/large child in rear if a captains' chair (6 seater) model so can stick legs forward between seats. Model X is very easy to get in and out of in front seats.
* Model 3 is trying to make this a more practical seating arrangement by making 5 adult-sized seats, something that basically the other 3 models Tesla has released have struggled to do. I think the Model 3 might even be better than the Model S, and maybe even better than the Model X, for 5 large adults. But, proof is in the pudding. I'd still like to know more, both about the Model 3 and the Model X, which I haven't spent a lot of sitting time in in the rear two rows, due to limited availability.
I used to commute in the rear of a small BMW as a 13 year old teenager. It was MISERABLE. I always hated that car. Being stuck in a car with bad room for me even as a child was AWFUL. I have never bought a small car since then, and yet, the large car I own now still has miserable back seat room. I applaud any effort given to fixing the rear seat problem. And since Tesla is trying to go to a much huger market, solving this problem of size for a large percentage of the population is a really good thing.