I like to define or put knife purchases in four categories.
First, there is the individual that buys a knife for personal use just because they like to carry a knife or it will be given as a gift. In this case such things as brand, blade composition and type often don’t factor in a lot. It’s more of the style, and cost that drives their decision.
Second, is the individual that buys a knife that will be used as a tool. In this case brand loyalty could be a factor, but the type of blade(s), number of blades, composition of the handle and the job for the knife is what will be the most important factors in their decision.
Third, is the individual that buys a variety of knives at wholesale for the purpose of resale in stores, flea markets or something like a knife and gun show. In this case it is important to have a large variety of knife types, styles and a good range of prices.
Fourth, is the collector. There could be as many different type of collectors as there are different types of knives. For collectors almost everything matters. Brand, style, type of blade, type of handle, age, condition and of course price. Serious collectors are not going to buy just any knife. They're looking for the best examples of the type of knives they are collecting and of course they are going to get it for the best possible price.
I'm retired, I'm not collecting to sell for profit at antique malls or trade shows, but I'm not above making a trade or two every now and then. My collection first started out as old pocket knives like a stockman, a trapper, or a Barlow. I bought some new ones also of the same styles. As I did more research and talk to more collectors I began to branch out and buy different brands and styles. I stayed with folding knives, but then a friend gave me a Ka-Bar from WWII so I've purchased a few straight blades, but not many. Most of those have gone to the grand kids for their collections.
So, no matter what category you fall into and regardless of what you collect, make it fun, share it with others and I hope it brings you joy.