And yet somehow you got the opposite idea; surely you aren't arguing that you were hoodwinked? What did you do as an undergrad? Were you unaware of this then? What made you start down the path to getting a PhD? I must admit that I was asleep or working for most of my undergraduate career, but I still knew that the apprenticeship toward "career after PhD" looked grim, even in my chosen field.
Every TA I ever had grumbled like you do. I'm sure every TA you had did too. And yet here you are.
I think the real problem is that somehow most people who are getting PhDs become convinced that they are worthless and have nothing to say and are thus paralized by the process. I have friends who took 15 years to get their PhD and I have friends who did it in 3 including required coursework. Do you know what the difference is? 12 miserable years. That's it.
I'm with Chuck on this one: write the fucking thesis. It's not your life's work; in fact, it's the opposite: it's the _first_ thing you'll ever do. So get it over with. No one cares except you, least of all your advisor.
/jordan