It's because Tesla has so few models. Every other manufacturer has an order of magnitude (or two orders) more models you can buy. Some brands have more EV models than Tesla does.
Just counting them, sure, but do they really? Most Auto makers cover reach segment, sub-compact, compact, full-size, and SUV, and just vary the offering within that class. Eg the Honda Civic sub-compact comes in EX, EX-L, LX, Type-R, Sport, Touring, and more. But meanwhile the Model S comes in a plethora of combinations of battery sizes and motor configs. Tesla covers 4 segments, full-size, compact, SUV (X) and SUV (Y). Other automakers do cover more eg sports and truck, but there's the roadster and the Cybertruck to contend with. Point being, if you just consider segments and configuration s per-segment, I'm not convinced Tesla is that far behind.
