Why not leave flight instruction to people that actually want to teach and make a career out of it and those that wish to be commercial pilots can head off in another direction? That way we won't be subjected to the endless stream of FI's that are just waiting till something better comes along, can't be ar*ed getting out of bed or have huge egos captaining their spam cans and pointing out constantly how incompetent us students are as we have a whole 200 hours less than them.
Look go and be an FI if you want to. If you want to earn £10 an hour and get 300 hours a year living from hand to mouth in some godforsaken back water then good on you and all the best, but do it for all the right reasons and not just to log some more hours. But please don't get all bitter and twisted when you realise after 3 years that you are no further in getting that elusive first job than the rest of us.