Not necessarily true. However the bigger concern is technology. The tech behind the batteries in a current generation Tesla will be probably one or two generations removed. Meaning, your going to get soaked on first generation buys.
Now Tesla does have swappable packs but the unknown is, how much will a replacement pack of second or third generation cost and will you be able to install it in the first generation car; I will assume you can.
The Tesla lower depreciation is factor of limited supply and the author is taking a mighty big bet that demand will remain as high as it is. Given Tesla's stated goals for manufacture and the models coming this is not a good bet.
Toss in that California may cap tax incentives to EVs costing 60k or less; I would push that to 40K or less. The rich should never have been given help to buy a car in a price range they already purchase in. This car certainly did not need the incentive.
You're not understanding the point of the rebate. Part of the purpose of the rebate is to finance car companies selling viable electric cars so that they can later on down the road make more affordable cars.