Agreed, but they don't need to be. Remember, the magic number here is ~1.4G, for a 1.9s 0-60. The Pilot Sport Cup 2 – a track-friendly R-compound tire used in the webcast car and in the videos – can pull close to that on a skidpad (i.e. less than optimal conditions), meaning the grip is there.
> I think it's straining credulity to believe that an electronic traction control system is going to outperform them to such a huge degree.
Launch control and traction control can make several tenths of seconds of difference, which is critical when you're talking about sub-2s times. Also, traction control can keep the car on the cusp of slip the entire run to 60MPH, which is critical in a car that has a completely flat torque curve and probably enough torque to break the wheels loose at any speed (which is not true for F1 cars).
I also suspect that the Roadster has active damping – another technology disallowed in F1 – meaning that the duration of contact with the road can be maximized. This is important if the road surface isn't glassy-smooth.
> This car also looks to weigh around double what an F1 car will weigh
That doesn't help it at all in cornering, but in a straight line, the increased weight of the car will help it launch even better since it'll increase the traction on the drive wheels (equivalent to downforce at speed).
> Gear changes: F1 gear changes take about 8 milliseconds. A road-going automatic gearbox is definitely not going to beat this.
There's no gearbox to speak of; the wheels are direct-drive. To be fair, this won't contribute significantly to faster 0-60 times, but the gearbox exists to compensate for some less-than-ideal characteristics of an ICE, namely uneven power delivery and physical limitations on peak RPMs. An electric motor has none of these problems.