The other likely alternative is that a fair percentage of reservations are holding off for other configurations...
I see many employees holding off for the base SR version.
I see some owners holding off for that, but more owners holding off for AWD and air-suspension....
Some may have jumped ship to a Model S/X, then after some thought cancelled their reservation.
In any case we don't have an update, but I'm expecting strong demand for Model 3 to continue and get stronger once the general public becomes more familiar with the car.
There many be competing BEVs, but not in high volumes as far as I can tell. So if you think the public will increasingly adopt BEVs (as I do) that more or less guarantees high Model 3 sales.