I think it continues to be under-appreciated how much of a lead Tesla still has in EVs. Even BMW can't make something that is practical. First people said "competition is coming" for about a decade. Now the competition has finally half arrived, but it's still so far behind. Perhaps the closest is BYD, but most BYD drivers would prefer to be driving a Tesla.
To have a broadly usable car, you need at least 50+ kWh battery, 100kWish fast charge, and basically almost everything you need in a big car. If you don't have it your car is not really usable as the main car.
Motors are small and efficient so they are not big cost drivers.
Small cars, such as 'cheap' B-segment cars still need all this stuff. If you look at the weight of something like a Renault 5, you find its not lighter than a Model 3. The manufacturer still pays for all that stuff, but the car's supposed to be cheap so they cant pass on the cost.
But in a small car, you have packaging problems with having to fit the battery pack, meaning you need to build them taller and draggier - that means your highway range decreases, and the big weight means big (and compact) crash structures, which again are more expensive.
In contrast, in a Model 3, you can make the pack thinner, design a more aerodynamic shape, have the big roomy frunk as a crash structure.
Your extra cost ist like tens of centimeters of steel and glass, but customers will happily pay more because its an upmarket car.
You can't really go beyond that, because the acceleration and torque is crazy even at the base level and at high speeds your range will still suck.
This basically means imo that the Model 3 and Y are at the ideal intersection of what the technology's good and bad at, and market positioning.
That's why I don't think Tesla will make a C-segment car.