Guvnor,
You ask "what other profession has line personnel being paid more than managers" - try the NHS (rather a large organisation). Surgeons and many of the senior doctors are paid substantially more than the hospital managers because they actually carry out the front-line work, rather than oversee it.
The reason that there is such a large turnover of cabin crew is that the job requires practically no qualifications and very little training. For you to say that cabin crew have an important job because they "sell and collect the revenue from duty free sales" is, frankly, laughable. You're obviously not aware that they receive a percentage of the take and so engage in this particular onerous task rather enthusiastically (often at the cost of a good service within the cabin).
I have no axe to grind with the engineers, the vast majority I have met are hard working, professional and good at their job. there is, however, a job hierarchy within every profession and most engineers will recognize that pilots come above them. No malice, just reality.
If there are any other unanswered questions that you need answers to then please feel free to post - many of us are more than able to give informed opinions due to our qualifications, both from present and previous professions.
Name-calling and insults are rarely called for as it is the domain of the ignorant, but in your case, you really are a total prat.