Slow denials is a feature not a bug of immigration systems. Fast denials with systems that allow retries just quickly get backlogs of people applying again after finding a quick fix to the rejection reason, which makes it harder to give proper time to new applicants who may be more eligible.

> Fast denials with systems that allow retries

There's nothing that says quick retries are allowed, or that subsequent tries should even be adjudicated quickly. Take H1Bs. If you get selected and subsequently denied, you can only apply next year.

Some types of visas require a cooldown period outside the country after you have used them. And so on. This is all solvable.

My point was to compare European countries as they were suggested by the GP to be better.

Go ahead and choose one or so and come back with numbers to compare. You'll find the US is very good in comparison.

Germany offers a shorter and significantly cheaper path to citizenship, for instance.

Plus incredibly easier paths to immigration on a skilled work permit and access to permanent residence. Like most EU countries.