I am not a professional nor do I have any experience in micro-stock photography so please excuse me if my comments seem out of place
I would imagine that if you are good professional photographer you would any way get a good bit of work with regards to "made to order" work. What I mean is that, my impression of micro-stock photography is that they produce generic pictures of everyday items. If you wanted to get a portrait done then you cant get it done through micro stock site can you ? Nor your wedding pics ? Nor the particular models or brands that you want in your print advert ?
I dont understand how micro-stock photography sites can take away busines from professional photographers as I see them as 2 distinct fields of photography.
Hope this makes sense and if not please forgive and ignore me