In my mind stainless steel knives were invented for those not willing to care for the blade steel well enough to prevent them from corroding. Not a bad idea. Stainless was created as a superior knife steel?
Ok, this is me rambling. I don't think any of what I'm going to say is absolutely without basis in fact, but I'm also not going to try to support it with hard science either. In fact, I would welcome input/criticism from anyone who has a solid background in metallurgy.
With that caveat in place, here we go.
First of all, stainless was not created as a superior knife steel because it wasn't developed for knives at all. I believe the man credited with inventing stainless steel was actually looking for a way to make superior gun barrels. It was created as a steel that didn't rust and someone later realized that knives could be made from it.
So it wasn't invented with knives in mind, but that doesn't mean much in terms of how good it is for that application. Is stainless a superior knife steel even if that's not why it was invented?
I don't like that question because I think it's impossible to answer. There are just too many stainless steels out there to make any kind of an assessment about their superiority or inferiority to carbon steel when it comes to knives. In fact, there are a lot of carbon steels out there too, so we're comparing a wide variety of things to a second wide variety of things. Some stainless steels are superior to some carbon steels. Some carbon steels are superior to some stainless steels. Some stainless steels make really poor knife blades, some make really good knife blades.
When a question is too hard, I like to take the politician's approach. I'm not going to answer the question that was asked, I'm going to make up my own question and answer it instead. Now don't get mad just yet--I'm going to try to make up a question that has an answer that is still sort of useful, and not totally off topic.
Here's the question. Let's say we pick a carbon steel and a stainless steel that have roughly similar material properties. Similar edge-holding, similar toughness, similar hardness. That's not a crazy assumption. Maybe one time it would have been, but these days it isn't hard to find a couple of really good knife steel alloys, one stainless and one carbon that match up very well in terms of hardness, toughness and edge-holding.
So now what's the difference between them?
Well, the stainless steel will probably be a little harder to sharpen. Stainless steels tend to be a little "stickier", in my experience and that makes them a little harder to sharpen. There are other reasons some stainless steels might be hard to sharpen that may be more pertinent, but let's leave it at that. Anyway, the stainless steel might also be a little less likely to chip, but that's just me speculating (then again, so is most of this post).
The stainless steel will definitely be more corrosion resistant.
Nothing like rambling in the middle of rambling--so here we go off on another tangent. What makes a knife dull? The way I think about it, four things make a knife edge dull.
1. Wear. The edge wears away from use.
2. Chipping. Pieces of the edge break off.
3. Rolling. The edge actually bends, or rolls over.
4. Corrosion. The edge corrodes away.
Depending on how the knife is used/carried/stored, and depending on what it's made of and how it's heat treated, the mix of how much each of those affects the knife's sharpness will vary.
Why did I bring that up? Well, by choosing a stainless knife, we can dramatically reduce one of the causes of dullness--corrosion. Now, if we pick a stainless steel that has other material properties that we like (toughness, edge retention, hardness) we can get everything we would have wanted out of a carbon steel knife with the extra benefit that we don't have to worry about corrosion either defacing our knife or dulling the edge. Maybe we pay a little bit of penalty in terms of sharpening ease, but for folks willing to sharpen on diamond hones, that's a pretty minor impact.
So are stainless steels superior to carbon steels for knives? I would say that there are SOME stainless steels available these days that can outperform traditional carbon steels used in knives in most categories without giving up anything appreciable in other areas. Obviously not all stainless steels fit that description, but there are some that do.
There is one big downside. If you want a knife made out of a stainless steel like that, you're almost certainly going to pay a lot more than you would for similar performance in a good carbon steel knife.
Anyway, ignoring the fact that I might have come up with a question that simplifies the the problem down to the point that it's meaningless, now we have an answer. Yeah, a really good stainless makes a superior knife steel.
So which stainless steel should you pick? You can always just pick a maker you trust instead and look at what they are using in their premium lines. They have experts who make knife steel decisions for a living. It's a complicated subject and most of us are never going to be able to get a really good handle on it.
Or you can find a bunch of resources and see what stainless steels are commonly recommended by people who claim to know what they're talking about. If you look at enough of them and sort of "average" out the recommendations, you'll probably end up with something decent.
Or, you can do what I did. You can read a bunch of stuff, watch a bunch of videos on knife steels and metallurgy, and knife material properties, ask dumb questions in online forums, read dumb questions other people have posted in online forums and then after you've done that for a good long time, you can start pretending like you have actually learned enough useful information to be able to discourse intelligently on the topic.
It's not an efficient approach to the problem, and if you try to prove how much you've learned in public, there's a good chance you'll get slapped down by someone who's actually a real expert. So I wouldn't take that approach that unless you really enjoy studying the topic. That way even if you never really gain much useful knowledge, at least you had fun just like I did.