I feel the entire argument about salary limits misses the forest for the trees. The goal of the legislation is to push EV adoption over ICE cars over a long timeframe. A rebate on EV cars is an effective way of achieving this. Irrespective of income levels, people are going to be incentivized to purchase an EV/PHEV (a nice gateway into a full EV) with such a policy in place. "Affordability" is a rather subjective term.
I'll offer myself as an example. Between my wife and I, we make more than enough to "afford" a Model Y or perhaps even a fancier car. But we drive 10+ year old cars because they work and are paid off and we choose to be more prudent with how we spend our money. There are others around us who probably make half our combined income who own less than 2 year old cars and even more expensive cars like the Model S / X. For them, affordability means something very different. For us, just because we have the money to spend on something, doesn't mean it is automatically affordable and worth spending on. At the end of the day, we're all on this planet this one time and people can choose to spend their money how they please and different people have different tolerance levels for how willingly they are going to part with their hard earned money on something that is more a splurge and less a necessity. The goal of the EV subsidy is to appeal to all of these folks. I'd probably wait several more years before taking the plunge with an EV if it hadn't been for the EV incentives being on the horizon. I'm sure I wouldn't be the only person in my situation.
As others have pointed out, the other side of the coin with boosting demand via this incentive is forcing manufacturers to respond with increased supply. The big automakers have been dragging their feet on EVs for a very long time and this will force them to respond. If you reduce the pool of people this subsidy applies to, you minimize the impact on demand and thus the impact you can exert on the supply curve as well.
Personally, I'm fine with the larger limits on income as long as they limit the dollar amount on the MSRP for vehicles eligible for the subsidy. At the end of the day, the M3 and MY are Tesla's entry-level offerings and you need the MSRP limit to capture these high volume EV vehicles from Tesla and other manufacturers so the policy can provide some meaningful long-term benefit.
