Job hunter I've read and re-read your post and can't help but suspect your problem is as much psychological and experiential. You do come across with a very real sense of hopelessness, perhaps created by optimism fatigue, and lacking in energy. I suggest you need to look at yourself and self-evaluate first, before expending energy in a job search which you feel is pointless (but which isn't).
A good place to start is with a complete re-write of your CV - start with a blank sheet of paper and just get all your points of experience, transferable skills etc down in whatever order they come to you. You can re-order them and make sense of them later. Look at what you are good at, what you have proved you can DO - and a little research on the net about methodologies you dont recognise to familiarise yourself with their core principles and applications - chances are you could easily pick them up if you can explain how your current experience effectively overlaps on to them anyway. Rise above the trends in methodologies and build the case from scratch about where you add value.
Also when looking at ads take a liberal view - they often describe a perfect fit as a way to try and minimise the amount of utterly unsuitable/purely aspirational responses. Yes there may be 500 other applicants, but boil out the ones which are simpy wasting time and you are probably down to maybe 30 or so credible applications. Believe it or not the 'perfect' candidate rarely gets the job - it is usually the one who is strong enough in enough areas, perfect in none particularly, but who can bring energy, vision, a can do attitude and who people want to work with who get the job.
Set yourself achieveble targets to help - such as number of jobs identified and applied to each week, number of catch up conversations with contacts/recruiters etc. Break it down into stages - rather than one target of 'get job'. And realise you have VALUE too - as an expert in your field and a human being. You want the right job, not just any job. Maybe you just haven't found that one yet.
Do try and get away from job hunting too - do something you enjoy and when you are not job hunting dont think about it, but enjoy whatever it is you are doing. Immerse yourself in each activity. If you feel yourself slipping into depression see a doc - can make a huge difference.
And remember there is always this forum to get some advice, blow off steam, or just share frustrations and progress.
Keep us up to date with how you get on.