Tree work in residential areas is expensive and many that haven't done it don't really have a grasp on why. It's often complicated, unforgiving and the potential for catastrophe is high. On Youtube, you can see the results of what happens when people take things into their own hands. Of course, most jobs don't go bad if done by amateurs but the likelihood is certainly higher.
Just from looking at the reach of the oak in this thread, considering it's California, I bet the bill would be a minimum of $8000. Making all that wood and debris go away would be a huge expense in and of itself. It's not going to fit in a chip truck... Mix in construction debris, glass and metal from the vehicle(s) and it's just a mess.