A 10.5 is only normal to arm-chair racers spoiled by the glut of 600+hp factory cars. Even 10 years ago, those times were reserved for hyper-cars, or stripped-out hotrods which were towed to the track.
Even today it's impressive to see a street car run under 12s. On a given test and tune night, I'll see maybe one out of 50 street cars run sub-11s, and they're always obviously modified.
You claim it isn't insane, yet your example is BMW's fastest car. I'll throw out another Definitely Not Insane Car running a similar time: Ferrari 488 GTB.
The point is that once you get up into this echelon of cars, 10.5 isn't game-changing. Chrysler built a car that will stomp the Model S, and it costs 20% less. For $100k you can build many cars that will outperform a Model S; 10.5 quarter mile isn't "insane" at that price if that's what you're optimizing for.
I suppose it's exhausting seeing Tesla marketing claim "fastest car ever!" because 0-60s are fast (which, as you said is mostly due to traction and the electric drivetrain). It's embarrassing when people start comparing the Model S performance to Ferraris and Lamborghinis. They aren't even in the same league when it comes to being race ready.
Source? On your wikipedia page it says 10.9 ... Also, it's currently more expensive than a Model S Performance.