What is described in the article sounds like a luxury to me, how do I get in, what do I do wrong, tell me?
As a perm employee for the past 20 years (four different employers), this isn't just limited to consultants. "You're a senior developer! You should already understand everything that exists!"
But maybe that's just me.
(I do think what you go through, where you get zero ramp up time, sounds pretty awful too.)
If you can, find out how much the middle-man company is farming you out for. Let's say you once did a contract through ManPower for ABC company. ABC company needs some labor, and you did a good job, so they reach out to you directly. You should be billing what ManPower billed your time for, not what you billed ManPower.
This is generally only possible to do through smaller businesses. Big corporations typically have contracts where they require you to go through one of their preferred vendors.