I suspect the same is true of many businesses that largely charge for their time - some are very well run and very profitable, others a complete disaster. I always find it fascinating to do the charge out rate sums of what could be charged, and compare these with what is actually charged AND paid. More often than not therein you have your answer.
It never ceases to amaze for how many businesses there are tried and tested formula and yet people try to rewrite the recipe book. The very best example is resteraunts. If you consider the average resteraunt that actually manages to produce good food it is superficially very difficult to understand why they dont make money, but the majority dont and the vast majority of new start ups fail in the first few years. They have no idea what their GP is and when they eventually find out they think 60% is ok. The sad truth is you cant make a resteraunt pay with a GP of 60% any more or less than you can make a garage or an aircraft maintenance op pay if you are only recovering 60% of your chargeable time; and recovering doesnt mean recorded hours on the time sheet, but money in the bank account (after bad debts
). After that have a viable model for the fixed costs and you will at least make a living.