I was trying to convey - & hope I succeeded - that I was not trying to blame or judge you, but the fact remains that from what you wrote, it sounds like the horse is desperate for better care, regardless whether it's anyone's fault. That might mean you're not the best owner for him.
You said he gets laminitis yearly and that due to his fear of men, he hadn't had his feet done in a long time and that while you try to tidy them up, you don't know how to trim them. In the above post however, you then say the horse hasn't foundered since you've had him. I'm confused by that contradiction. You say he's on a 'strict' diet of hay & pasture, which if your first assertion about yearly foundering is correct, sounds like it is not good for him. Safergrass.org is one place you can learn more about the dietary/metabolic side of founder.
Regarding his fear, yes, change in environment will have made him less secure, so his emotional reactions are likely to be stronger too. I think if you've been working on this issue with little progress for years, then if possible, it would help to find a good, considerate & understanding horseperson to work with. Failing(or in addition to) that, learning about 'clicker training' is a great approach, especially with fearful/traumatised animals, to get them over it. As he's so desperate for hoofcare, I would also strongly consider using sedatives or even knocking him out, to get the regular care he needs, rather than leaving it (months, years?) longer in the hope you get him over his fear first.