I don't disagree with your thoughts. I think it is clear that the newer technology metal detectors offer a significant performance leap over the old technology machines. I also think that the newer machines (in general) offer numerous other benefits as well - ergonomics. light weight, useful features, etc..
However..
To the extent that faith/trust [in your machine] plays a role; I have no difficulty believing a proficient hunter (someone who is one with his/her machine) can have more success with their old technology machine (that they know and trust) than they would have with a new technology machine. Not every machine is a fit for every user - sometimes the most capable machine isn't the machine that gives some hunters the most performance.
I know [personal experience] that hunting with a top-performing machine that I just don't gel with - isn't much fun, or very rewarding as far as finds go.
I do try to buy/use machines that I believe offer a performance advantage - but I find it far more important to own/use machines that speak a language that I instinctually understand. For me, metal detecting is something I do for enjoyment; so owning/using machines that I enjoy using is an absolute must. Otherwise the hobby could become a task that I don't really want to engage in.
I suspect I approach metal detecting from a standpoint that is different (from yours). I know I miss good targets, but that doesn't concern me since I hunt the same areas over and over (different directions, different coils, different machines, etc..). I enjoy metal detecting for the "unknown" factor - who lost it, what was their life like, etc.. Questions that likely won't be answered in most cases. For me it isn't so much about the targets found - as it is the questions (in my mind) about the circumstances involving said target.
I am very much looking forward to your thoughts on the Deus II and the new smf machine from NM. If the NM machine performs as well as I hope - I'll buy one. I doubt that I'll buy the Deus II though as I'm not a water hunter so it doesn't seem as though it offers enough benefit (for my kind of hunting) to justify the cost.