Its an interesting question. I'm not a union guy and spent my youth working in construction so I've encountered my share of plodding union tradesmen who took remarkably long to do small things that could be finished in a few minutes if you rushed. When I was young and foolish I'd often shake my head at the snails-pace they worked at.
I'm older now, and arguably a smidgen wiser. I've reacted with shock at hearing about old acquaintances who have been killed on the job or now endure chronic pain and are no longer able to work. Broken backs, bum knees, busted nerves, missing fingers, the list goes on. The plodding, methodical 55 year-old union guy is looking less and less silly the older I get.
In short, perhaps one reason a union might push back against performance-based bonuses is that it often ends up coming at a long-term cost to the worker that is difficult to foresee when you're an invincible 25 year-old trying to make a few extra bucks for the weekend.
Say you're laying rail track. It will be used for 50+ years. Better to lay it once, relatively slowly, and well than to do a shoddy quick job and have to repair it every 5 years.
Perhaps another argument for the plodding, methodical 55 year-old union guy's way of working?
But the union don't recommend things for engineering reasons though, do they? That's not their remit and they don't represent users of the railway or future maintainers of the railway. They represent the employees today.
In fact the incentive of the union is shoddier work so they have more work to do late to replace it.
Worked with unions before - some are definitely better than others and some are really great at their jobs, efficient and good quality work. Some are REALLY bad - all the slow inefficient protectionist BS you hear about, they're definitely out there and it's not because they're more careful about quality.
I really don't know the ratio, but in my highly incomplete experience it was about 50/50..
This is purely conjecture, but the real problem to me SEEMS to be the union management. Unions are super useful sometimes, but like any concentration of power, they get corrupt over time.
Well, it is not the first time I hear such stories. Not only from the US either. At my own job we sometimes work at unionized places and it is the same everywhere. Horrendously en ridiculously inefficient work practices. It certainly gives me a very negative image of unions.
