Move diecast to TOYS. They are readily available and in production. I stock over 400 specialty diecast models in stock that I can reorder at will, and why and how is that categorized as "collectible?"
The balance of my stock that I can't readily order is collectible, and I might cross-list that into "collectible." because models I can't readily replace from the wholesale catalogues ARE collectible, but are the minority share of my inventory.
Diecast replicas are also usually purchased by collectors who are buying in a SUBJECT category, not a BRAND category. I see too many brands (so add MOdel Power for one, it's the first model brand I tried moving into your diecast category and there's no category for model power..lol) and not a single SUBJECT.
Like: "Diecast Airplanes" etc
Cars, trucks, Ships, Fire engines, Helicopters, Police cars
That's what my traffic analysis from somewhere else where they define me as a "powerful seller" says. I have brands in my titles and tags, but the searches are almost always by subject.
"diecast airplanes" "Model airplane" "diecast ships"
and so on.....