I agree with posts suggesting that FI ratings should not be taken lightly as simply a stepping stone. It would be a great thing for the aviation industry as a whole if people wanted to train as Flight Instructors so that they can spend a career passing on knowledge to others. Unfortunately though, the carrer path is simply not there - job security, terms and conditons etc. Thus, Flight Instructing is an obvious and relatively straight forward path for developing ones flying career.
The route of Air Taxi and twins is a difficuilt one as many operators of such aircraft are very reluctant to give Single Pilot jobs flying pax to inexperienced pilots. Flying light twins around single pilot is a challenging job and thus employers tend to go for pilots with quite a few hours. In my experience, they usually prefer to employ ex instructors with a 1000 hours or so who have been conducting multi training. (One of the big reasons is the experience levels dictated to the company by insurance companies).
Thus, we get to the very familiar problem of how to get experience! Yes, aerial work is a path one can take but how many aerial photography companies are there really. Also, how many pilots does a parachute club really need?
So the difficuilt situation exists at the end of ones training. 250 hour fATPL and no experience. No local parachute club looking for pilots. No local aerial photography company. Aerial survey - no. Air Taxi company wants 1000hrs. The usual difficuilty of getting an interview for a regional F/O job. All seems desperate. Yet there is the Flight Instructors rating. Something that keeps your career moving. And most peolpe who become FI are very determined to succeed and thus put a lot of effort and dedication into instructing.
Yes it is a shame that just as Instructors get to a high level of skill in their job they move onto regionals, air taxi etc but unfortunately that is the reality for the training indstry. Such a discussion is really the topic for another thread. People will still make their own decisions in the pursuit of flying. There is no one guaranteed path to the dizzying heights of Jets. My only real advice to people is don't give up, keep your log book moving any way you can and enjoy your time in General Aviation - its where you do real flying!