I can't find where that article is getting $90 an hour, I'm seeing 28 an hour starting, with 42 an hour as a max in 2028 (which isn't to say anything about the people in probation; we shouldn't forget people sometimes have to work for years to earn their way into a union). This would suggest the salary is lower than at Tesla (at least according to Reuters) https://www.reuters.com/business/autos-transportation/gms-la...

From the studies I've seen, factory unions pay the most at formation, and after 5 years they fall to 1-2% above comparable factories in regards to total compensation. This makes sense, as union contracts are usually negotiated against industry averages, and no offense to joe schmo from aluminum castings but the Harvard MBA in charge of negotiating for the company is usually a better negotiator.