> Another aspect is that salaries are very even across much of the industry, as it is often negotiated by unions

Can you specify what country you're drawing these facts from? Europe does not have standard employment law, and I definitely haven't experienced salaries being set by unions or being common across the industry.

Germany in this case. The high tax rates at progressive rates mean that salary increases mean that income after taxes is quite flat.

There are also union negotiated rates for pay across much of the industry. Even if you switch employer your pay might remain exactly the same, unless you also get promoted and into a higher level or a different industry. "Flächentarifvertrag" it is called.

Obviously this drastically disincentivizes hoping employers.

> Germany in this case. The high tax rates at progressive rates mean that salary increases mean that income after taxes is quite flat.

OK, good to know. I definitely haven't experienced flat income after taxes post salary bump, even though I pay 52% marginal on my income (in Ireland).

> Obviously this drastically disincentivizes hoping employers.

I can totally see that. Is it really that common in tech jobs though? I'd have expected this to be much more common in larger, older companies (like the automotive industry).

>I can totally see that. Is it really that common in tech jobs

What is a "tech job"? Wouldn't a job where you are designing the electrical/mechanical/software parts of a car be a "tech job"?

Of course this is much more common in older, well established industries. But that is where most of the "tech jobs" are. Germany, especially labor laws, are hostile to start-ups so it is natural that people get employed at these older companies with union negotiated salaries.