I don't think this has to do with the car being aluminium. Service King has guys that do work and it's not even 2x the hourly rate (see their rates in the lobby next time you're there). Parts availability is not affected by aluminium or steel, it's all on the manufacturer, in this case Tesla.
With relatively low volumes, Tesla's tight control of not allowing secondary market pars, and the fact that cars chance so fast (every 2 weeks according to Elon), it is less likely that a secondary parts manufacturer will fill in the gap any time soon. When you get an exotic, hand-made car, you're stuck waiting for parts but at least there are not a lot of people waiting as they don't sell a lot. When you have a mass market car, they only change every 4 years or so and have the market size to justify a parts supply chain and secondary part sources (often same parts are used in different models too). Tesla is the worst of the two world, they make custom, ever-changing/no-two-alike cars at a 50K per year volume which creates a line of people waiting for custom parts but not long enough of a line for the industry to create a solution it could profit on. Similar story with the expertise to estimate and fix them. With the cars changing so fast, it takes a lot to keep up to date on it. Service King has one expert for Teslas.
