In most places, you apply directly to the team you would be working for, and once they have decided they want you, it is in their interest to push the bureaucra

In most places, you apply directly to the team you would be working for, and once they have decided they want you, it is in their interest to push the bureaucracy on your behalf, so things tend to move (at least somewhat) briskly. But that's not how it works at Google. You apply to a broad category of jobs, and only after Google has decided they want you do they try to figure out what team gets you. During the screening process no one inside the company has a stake in you, so no one is pushing the bureaucracy, which means things move slowly. If Google wanted to change all of this, they could, but I suspect not much will be done. Google has a lot of highly qualified applicants and even though their process is frustrating, the output of their hiring pipeline is a very fine set of engineers. So Google doesn't have much incentive to change.