You hold it in your hand and presumably it will cut.

Pretty much the reason for being, and definition of, a knife. What more do you want?

You could likely get similar cutting performance for a lot less money. But there is the human factor. It is not just a knife. It is going to be Your knife and it is fairly important that it works well for you, that you like it and and that you have some level of confidence in it. So the 'lowest bidder meeting the minimum requirement' approach may not be the best way.

How much more your willing to spend to bridge the difference between 'what works' and what works for you is entirely a decision between you, your self-image and, your wallet.

IMO there are perfectly functional and useful knives out there for $10 and up depending on size, name brand and features.

Many of our ancestors got by in much tougher times than we are likely to see with some pretty marginal blades. For every Jim Bowie masterpiece or knife forged and ground out in a workmanlike manner by a craftsman there were thousands of knives crudely hacked out of any available material and pressed into use. If you try you can find knives that are nearly useless today, often stamped out of stainless only suitable for soup spoons, but as long as you avoid the no-name producers and discount flea market knives it is pretty hard to find one that doesn't have some merits.

The general quality of steel used and craftsmanship applied has risen steadily over the last thirty years. Used to be the market was flooded with cheap Indian and Bangladeshi knock-offs of buck knives selling for about $5. Sometimes as low as $2. Now for not much more than that price, usually about $10, you can find a functional model made of a perfectly serviceable steel.

IMHO the sweet spot, where you get the most knife for the least amount of money, for a functional fixed-blade knife with a roughly 4" blade is about $50. Sometimes a bit more or less.

You can spend a lot more but, for the most part, your not buying function. Your buying a name or serving a psychological need for style or uniqueness, imagined reliability or capability. Nothing wrong with that as long as you can afford the indulgence and your aware of what is driving you.

I have seen people spend a load of money on a knife that becomes something of a signature. Many an otherwise gray functionary has set himself apart by being the guy with the custom blade. As long as they can afford to buy it without neglecting something else, or thinking it makes them special, I'm unconcerned and happy that they like their knife.

Unfortunately in this consumerist society a lot of people try to buy skill by buying the higher dollar tool. They overlook that the performance and effectiveness of a tool largely comes from the hand holding it. I have seen remarkable feats of field craft done with a $7 Boyscout knife and I have seen high dollar custom knives so ineptly handled that they were a detriment to getting anything done and a hazard to everyone around them.