Don't know much about unions in the automotive industry, other than they exist. Is anyone a part of the UAW? Who can explain how it works, and whether they think it's beneficial?
Unions are mostly used for "collective bargaining." You pay fees to pay people to lobby for TC on your behalf. Those fees help pay you a percentage of your pay when those people say "don't show up to work - we're on strike until we get more TC" even if your product isn't selling or your skillset hasn't improved - Unions will fight to keep your complacency employed with continuous periodic raises at the cost of employer margins. Employer bottom line can be impacted and may necessitate layoffs or site shutdowns when it no longer makes sense to keep paying for employees whose labor costs went up while overall revenue and profit did not.
Here’s how it works: people who are not auto workers take your money, and give it to politicians who are also not auto workers and use it to pay for their BMWs. You get an inflated salary for a while and then your job goes away.