i agree with most of your comment Rob, but having been in or associated with the outdoor industry for all of my working life i think there's a pretty clear dividing line as far as quality/suitability & pricing goes. currently it's broadly about £200, IMO (feel free to shoot me down here)
this is in line with quality mountaineering jackets which are effectively doing the same thing. having owned a vision sade for a number of years i can vouch for their quality, so i presume the same can be said for their kust, lohi & vene which are essentially the same construction
the higher end jackets are worth it to a degree. for instance the "basic" simms guide at just over £300 is bomb-proof, similar construction to a top-end mountaineering jacket & around the same price. also backed up not just by simms, but a Goretex warranty which in my experience is worth paying for. once you start adding on loads of extra pockets & dangly bits the price sky-rockets and you have to ask yourself....
the fishing jackets i really take issue with are the sub-£100 ones or maybe slightly more that are normally not worth buying at all. typically these will have a liner of some kind, be with some generic membrane, covered in pockets etc, poorly designed cuffs & hoods etc. someone's bound to pop up and tell me they found something perfect at this level... well, horses for courses.
just as a point of interest, the kayak cag i'm wearing in the photo is the sort of thing worn by touring sea kayakers for multi-day trips and has a full hood. at this level of performance they retail at around the £200 mark too....