This exact deal is not open to any other company. This isn't a policy that's open for everyone to take advantage of in the way that some tax breaks are, e.g. for film makers.
Just because other deals like this have also occurred doesn't mean this one isn't also singular and specific. Don't know why you're getting pedantic on this.
Again, this is a particular application of a long-standing, widely-applicable policy on the part of the state of Nevada. It's very similar to, and just as anti-free-market as, a company with pricing tiers of
$50 / month: bad service
$400 / month: we respond to your emails
$2000 / month: you can page a support engineer at any time
If you need more, call us: XXX-XXX-XXXX
Tesla, like so many other companies, is operating at the "call us" level of service (what you describe as "this exact deal is not open to any other company"). The currency they're spending is voter satisfaction instead of dollars.
Asking local governments for tax breaks is part of the process of siting factories. The terms vary from case to case, which is completely normal in the free market. That's how all major transactions are negotiated. But yes, this is a policy anyone can benefit from, as long as they're siting a factory or doing something similarly exciting to politicians.
Just because other deals like this have also occurred doesn't mean this one isn't also singular and specific. Don't know why you're getting pedantic on this.