These UAW workers are one of the last bastions of blue collar employees that still have some power and can occasionally demand higher wages, this new contract will last 6 years and there won't be any increases outside of what they bargained for and are contractual.
Asd someone who spent 28 years in the same union, I have seen executive pay rise steadily over that entire period while guys on the shop floor are paid peanuts. The real kicker is "profit sharing", where as each business unit would calculate their profits at years end and give a portion to the employees. About 5 years into my career they took that from us, and many of the lower level salaried and managment employees got profit sharing checks that were in the $50K to $70K range. I worked with those guys who got those, and the upper management was six figures.
Of course, when times are tough, and they would get that way (2008) they would just cancel profit sharing for their employees, but they were still making great salaries. When things picked up, they would start profit sharing again. With the union side, everything was contractual. The only time that unexpected raises to salary were made by the company was when they did a "review" which called for this, and that was only because they were having a hard time retaining employees, who were leaving for more money elsewhere.