> I'm surprised not at those uses, but that anyone would use a fancy steel knife for any of them.

Speaking only for myself - I get enjoyment from using quality tools. That goes for knives, but it’s also why I invested in Milwaukee M18 Fuel power tools when the much cheaper Ryobi line would technically have met my needs. It’s also why I use vim and have spent as much time as I have customizing it to my liking.

For knives, there are three that I regularly carry:

For everyday use, I always have my Microtech UTX-85 D/E (~$250). It’s an OTF (“out the front”), the blade is ELMAX, and is easily opened with one hand. While I originally chose it primarily for defensive use - I often carry a full-sized handgun OWB, and it’s well suited for use as a retention tool - I’ve found its ability to hold an edge and ease of opening makes it ideal for everyday tasks like opening packages. If I had to do it over I would buy the single-edged version; the double edge makes it difficult sometimes to get leverage when cutting something stubborn.

I usually carry a second knife that’s sturdier and well-suited for “serious cutting”. If I need to open a thick plastic package, or (gently) pry on something, I use it. It’s a Gerber US-Assist (~$100). The blade is S30V, and has a nice, thick spine that I can lay my finger on to gain good control. It also a locking blade (so it can’t fold on my fingers when using it) and has a safety button so the blade can be affirmatively locked either open or closed.

Finally, for food purposes only, I have a CRKT CEO (~$50). Its blade is commodity steel (“8Cr13MoV”, I had to look it up), and it holds an edge adequately. Pretty much every time I use it, I touch up the edge that night so it stays razor sharp. Because I’m mostly cutting meat with it I chose a long, slender blade with a gentle curve. Since getting it I’ve found myself increasingly annoyed when I unexpectedly go out to eat and end up having to tear a steak with a dull serrated steak knife provided at a restaurant.

> I have a utility knife that takes replaceable utility knife blades, and I'd think having a replaceable blade would work best for any of those things.

If I were regularly using a knife for cutting boxes, tape, plastic, etc., I’d do the same. Many years ago when I was working as an electrician, I had a folding knife that used standard utility knife blades. When I was working in PC Support at a large company and was often opening boxes and breaking them down to be crushed, I carried it as well.

I carry a single expensive knife (my Microtech) because I like it. It’s not that complicated :). I have other knives for specific purposes, and carry them when I expect I might need them - but in a pinch, the Microtech can serve almost any role adequately well. A good steel will hold an edge very well and give you that flexibility - I don’t hesitate to cut anything with it. Meanwhile, I would never use the slender generic steel blade of my “food knife” to open a plastic package that might have metal staples; it would destroy the edge and would at least take time and effort to restore the edge. I might even have to reprofile it.

All of this is to say: I highly recommend that everyone carry a good quality, general purpose pocketknife. They can be had at any budget level and you’ll use it far more than you’d expect. Beyond that... spending more money and acquiring knives for specific purposes is something you either enjoy or you don’t.