I've been a self-employed IC with numerous large clients and I currently work for a company that I'm an actual employee, but my company contracts me out to anot

I've been a self-employed IC with numerous large clients and I currently work for a company that I'm an actual employee, but my company contracts me out to another company. I've done this for over 15 years and none of what you're describing has been my experience. Did you even negotiate the transition or did you just accept what your company told you? How often have you gone through this?