Been in to knives for a very long time, it really depends on you and your use case/wants. With guns, going custom can gain you accuracy, reliability, and customization, while there are amazingly accurate factory rifles, even some expensive factory ones are inconsistently so. Many factory knives use better steel with great heat treating, have durable/reliable/strong lockups, handles etc, so the only thing that you really gain going custom is if you want something custom/unique or a design you can't find. Also much like custom gun makers, there are a lot of custom knife makers doing subpar work that's no better, and in some cases worse than factory knives when it comes to steel and heat treat. The blade steel and heat treatment for your use case can be more complicated than having an argument on a gun forum of what caliber to shoot and the best cleaning method at the same time. The blade steels that hold their edge the longest are the most brittle and easiest to damage and hardest to sharpen that damage out of. Edge geometry and heat treat matter a lot as well. Many times the heat treat and blade steel are chosen not for performance but for economy, softer steels and heat treats are faster to grind and you get more knives ground out per belt etc. Like many industries if the company thinks they can get away cheap without most customers knowing, they will cut corners.
With custom knives to me they are more like watches, a Rolex doesn't tell time more accurately or take more abuse than a G-shock, but it's a fashion statement, and it's something that can be handed down to your kids etc. However as far as the most accurate durable watch the G-shock wins. The other difference is most of us can tell right away if a gun is going to shoot well, however most knife enthusiasts can't tell you if a blade is really the steel it says it is, or if it's been heat treated to the stated range. It's much harder to judge performance.
It really depends on if you are more about form, or function, tons of production knives will get you 100% or more of the cutting performance of most custom knives, but they aren't a status symbol or an heirloom piece.
There's also the statement of use others have made, if I have a utility knife, or a $60 knife I'm going to be more willing to abuse it, than if it's a $1000 custom. If you're opening packages 90% of the time with your knife, no knife will ever do that as well as a simple box cutter. One has to remember at the end of the day a pocket knife was designed as a significant compromise for a larger, stronger, less complicated less likely to fail fixed blade so it could go in your pocket.
