Having a halo product can be inspiring. A lot of BMW buyers may get a boring old 3 series but they like that the low volume M cars exist, for example.

If Tesla wanted to be BMW they could just do all the BMW things. But they are aspiring for more, so they flip the script quite often. I'm not arguing for or against their decisions; just saying that because BMW does it is not a good argument for them.

Maybe they will finally release the Roadster to serve this purpose

Just buy an i4, even the eDrive is pretty zippy 0-60 in 5.4 seconds (the M50 can do it in 3.1 seconds). I’m not sure what the M car EV will look like beyond a motor for every wheel, but I can’t really see a point to it.