I've not lost interest, but money has made it more difficult for me. I see folks on here getting new stuff almost every week now and that's just not feasible for me monetarily. I now have to keep a flat going all by myself (it was being shared with my Dad prior to his passing last year). I still nab bits where I can, but the idea of having loads and loads of variety doesn't appeal to me as much as it did a few years ago. I've now got maybe 6 soaps in the den for example, whereas at it's peak I had 30-40. I had 10+ razors and now have maybe 3, with a Rex Envoy that I'm going to be paying for shortly adding to that.
Chris, if you don't mind me asking do you have any other hobbies?
I participate in a few online forums for my hobbies over the years, buying records/music technology/recording gear, guitars and shaving, and I'd say they all have the same patterns of behaviour with newcomers learning of ways to improve their set up at all segments of the market (low, mid, high end).
Part of it, that often the thrill of the chase (the research, the order and waiting for the item to be delivered) is more enjoyable than actually using the product itself, and after time it's get to a stage where you have more microphones/guitars/razors/[insert name of object associated to hobby] than you need and either the user will continue to buy/sell objects or move onto to another hobby.
I've never really fallen into the rabbit hole of expensive razors/soaps and so on as in my other hobbies for chasing rare/elusive items I once spent a ridiculous sum of money on a hand built acoustic guitar which sounded beautiful but I never bonded with it like I did with the acoustic guitar I played the most. Buying that high end object for my hobby didn't satisfy the urge as for my mindset it never could happen, it's the mindset of someone with addictive traits.
I can only speak for myself though, it's not to describe the patterns of behaviour for anyone else and it's important to find out what works for the individual as we all have different paths on this particular journey in this hobby (and others).