Where Tesla is alone is the rate of increase in their manufacturing capacity and technology. Older companies of course build and upgrade new factories, but Tesla started with no assets just 15 years ago, so on a relative basis that capex is a much higher percentage of the company and has been the entire time, compared to say GM or BMW. GM and Tesla both spending the same amount on new factories is a very different equation for the two companies, and my point is that as time goes on it is less so that way
I think the tax credits helped them keep the price as high as they needed to to cover their higher costs, at the time. In the end, your goal as a company is to set the price as high as possible regardless of tax credits, and get the costs as low as possible. Luckily for Tesla there was demand for the Model S at prices then that fewer would pay now, because it was really the only EV option (no longer the case) and thus early adopters were willing to pay more for that perceived emotional benefit. In addition, as capacity has expanded and initial capital investment is amortized, you can maintain good margins at lower prices. The EV credit was a market disruption that simply allowed them to increase the price $7500 - and the car was still net net much more expensive than it is now backing those rebates out.
So my point here - tax credits helped Tesla survive, and price reductions in concert with the elimination of credits aren't necessarily a causal relationship. Economc theory suggests the vast majority of those credits went straight to Tesla, not to consumers, as consumers would factor in the rebate in their purchase decision. This also explains GM's price reductions, because consumers always had an affordability or value requirement for what they are getting. The difference with Tesla is you are looking at 20-30k price reductions, and dramatic bundling of previously expensive options on top, thus making the comparison to an 8.5k price reduction from GM moot.
