I completely agree. There was this really expensive tutor I used to go to that charged $100 a lesson. They encouraged not going to school just to attend tutoring classes during the day (during the hsc btw). Encouraged forsaking all subjects except math, and they forced people into dropping 4u because the tutor perceived it as a waste of time.
Gave ridiculous amounts of homework which was expected to be completed (literally 50 pages every week), and if it wasn't completed, they actually issued detention. No matter how much money parents invest in a tutor or child, if the tutor (or child) has a bad attitude or mentality, the kid will probably not succeed. I do think tutors have an important role not only as an individual that teaches content, but as someone who motivates and keeps the kid on track.
I failed all my subjects in year 11, and did quite averagely in maths. When I dropped just before the HSC started, it gave me the time to concentrate on my school work, rather than what the tutor's work. All my ranks went up, and although I bombed 3u maths, I think i would've bombed my hsc if i stayed.