I think you are missing the point that it's only a pain point for countries with a backlog, not ones without a backlog. 3-4 years in the grand scheme of things is not all that long for gaining PR of a different country.
On top of that, the pain is extra bad for people from India, where the queue wait is effectively infinite. While for Chinese people it's a relatively tractable 5 years last time I checked.
The longest part of the process is the labor market test to ensure there are no willing, able and qualified American workers. This includes advertising the position in a number of different locations and channels for a set number of days and interviewing any American workers that apply.