I am a very experienced instructor/examiner and in recent times i have had several rookie instructors who are finding it difficult financially ask me why the pay and conditions are so bad, considering that they are now a professional pilot and teacher of aviation. I really do not have a definitive answer for them !!
There are many possible reasons, i have asked other instructors what they thought were the reasons for low pay -
Lack of union representation ?
That the job is of little importance in general ?
Bad management of schools ?
Hour builders?
Seasonal weather ?
Obviously financial reward is one of the main reasons for working, the mortgage and bills have to be paid, so serious consideration has to be given prior to moving into this trade and many people have come unstuck.
However if money is no problem for you instructing can be a very pleasant job.
Personally i think that in general that the job of flying instructor needs a new identity and with much better pay, condition and prospects. The skills, qualifications and responsibility of the job are not matched to the rewards.
Also as a previous post has mentioned - you will be a teacher and you need certain qualities to be a successful teacher. Many do not have these qualities !!!