The magic is gone? I don't think so. I think people are just tired of waiting months (or having to cough up more money) only to continue to wait even longer for their Model 3. It's as simple as that. Also, Elon Musk's tweets have nothing to do with any of that and it's just stupid to imply otherwise.
There isn’t a single leading reason why people are deciding to cancel their Model 3 orders, but there’s a couple of possible explanations: the car felt like it wasn’t worth the wait anymore (the Tesla website promises a 1-3 month wait time, but the reported wait time allegedly ranges from four months to a year, to as late as 2020).