The key is : What is one getting for monies spent?
For a simple example allow me to use a Old Hickory Paring knife one can purchase at the Mom & Pop Hardware store for about $3.
$3 is a lot of money for a person with say a spouse dying of cancer, or a child terminally ill.
$3 is pocket change to many folks, that much is probably loose in the bottom of a purse, console of vehicle or desk drawer at work.
Now this paring knife with a 3 1/4" carbon steel 1095 is easy to sharpen, holds an edge, and is proven in the kitchen, the garden, dressing game, cleaning fish , opening boxes, cutting string, rope...
...and has been used to stop an immediate threat / used to commit serious crimes against persons resulting in injury and death.
Contrast
There are some kitchen knives that sell for more money, with fancier handles, and steels that come with special edges (serrated and such). One cannot "really" sharpen these, basically designed to be disposed of when "dull". The steels do not have the "elasticity" of the Old Hickory so therefore more prone to "snap".
Knives, guns, and anything else boils down to Software-not-Hardware, common sense, tool for task, budget, "fit to user" , "knowing how to use a tool" and one big key is what works for YOU and accepting what another uses- may not be best for YOU.
Locking knives with great steel are great, unless one is in the UK. One has to know the legal aspects as well now-a-days as well. UK is not allowed locking knives or blades longer than 3".
$3 Old Hickory 3 1/4" paring knife I can legally carry in my jurisdiction, it is under the 3 1/2 " legal limits.
Oh, I do have a personal thing about my intelligence being insulted. Do not mark something , say my example of a $3 Old Hickory knife up to $6 and tell me it is "on sale" or "50% off" and I can buy it for $3.
Bottom line is, I am getting a certain OH paring knife for $3 , and I am getting what I am getting for monies spent.
Now if Mom & Pop sell it to me for $2.50, then and only then did I get a special deal.
No Holy Grails in anything.
My point is - as John touched on - point of diminishing returns and pride of ownership.
Would a custom Ivory handle on that $3 OH knife make it a better defensive knife? Nope.
It would only mean something to me, if I were take pride of ownership in having this done and "customized" to my liking.
Now for me, a bit bigger handle, and some other "fit to my hands" would indeed make this $3 OH paring knife a better defensive tool, with a quality leather sheath.
More money invested in training to use it, the handle and sheath than the blade steel itself.
Same as a used police trade in Model 10 for CCW. Stocks to fit, training, trigger time and holster to fit me.
hso-
How we doing on "that" project? *grin*
Steve