First and most important:
I really feel for you, that you obviously have had so much bad luck, to be put on hold with every order. And therefore I really understand, that you are totally p***d. Most likely I would be too. But - though no reassurence for you - that is not as common, as it might seem to you. Whenever I ordered spare parts (most often displays I broke 
, they were deilvered right away. The crowdfunding for FP1 of course was something different; but that was to be expected.
You seem to know a lot. 
My thoughts on those points:
- Is it really bad management or bad supply chain control?
Shit happens all the time; and most often unexpected. Since you already stated, that Fairphone are still operating in a niche, they simply do not have the means (financially, logistically, workforcewise) to prepare for every occasion. And therefore unforeseen trouble can result in heavy delays. (The homepage states, that they hope to have it back in stock end October; this should mean, that recent orders have been served by then already.)
- Who placed the order when and - maybe more important - where.
Possibly some users ordered from memolife or vireo or another reseller. Since those resellers surely got their own stock first off, one could order with them later and still receive the camera sooner. So, no need to doubt the “first in - first out” principle with Fairphone.
Vireo still offers the set at 69.90 Euro giving a delivery time of 1 to 3 days. So, they seem to still have some stock.
You might be right, that Fairphone will struggle to get out of the niche, with deliveries like that. Still this happens all the time, when demand for a product is much higher than expected or when things go wrong; even with the big companies like Apple, Samsung, Volkswagen …
As I see it, the way won’t be a really short and fast one. But up to now, they have taken up speed with every new phone; therefore I am still positive and would give them some time. 