Uhhh... no. Sorry, you're flat wrong about that. You completely misread my post/intent. That's not at all what I meant.
Steel chemistry absolutely matters. It matters a great deal. One cannot polish a turd, nor can one drink whiskey from a bottle of wine. Likewise, no amount of HT "magic" can ever improve the inherent chemistry in any alloy.
For instance, there is a dang good reason Ka-Bar/Becker uses 1095CV instead of "plain" 1095, and why Buck generally uses 420HC instead of 420J... They're demonstrably better than the cheaper, easier-to-machine versions. Both companies have their HT dialed-in pretty well to reach the higher potential of the better materials they've selected.
Half-vast steel with good HT is "not terrible". 440A/420J/AUS-6 is half-vast steel when judged by today's standards for cutlery. It will work, for a while. Put it next to excellent steel with excellent HT and the same geometry, and it's gonna get blown out of the water.
I guess my question then would be what counts as "getting blown of the water." For something like a kitchen knife, I require it to cut well, and stay sharp for an extended period of time. I'm not sure what else is really necessary for those purposes, and I can say for a fact that my Cutco knives, despite daily use, stay sharper for longer than my Benchmade Nimravus under the same use, or my Spyderco Manix 2 in S30V. Or any of my Beckers, including the BK5. In my experience, 1095CV dulls fairly quickly on a cutting board, although I'll grant you that all of those blades have different edge geometries.
That's not to say that chemistry doesn't matter at all, or otherwise has no effect. I think you'll be hard pressed to find someone who knows a bit about blade steels who would disagree, and there's certainly a number of reasons why I prefer to use CPM 3V for my larger blades that have everything to do with chemistry. And one of the big issues with 440 in general is that it's not terrifically strong. My Cutco vegetable knife broke during the move (within the handle, interestingly enough), and I haven't gotten around to using the "Forever Guarantee" to have it replaced. It's not like it's terribly weak either though. I've put the cleaver to a number of rather difficult tasks, such as chopping up frozen chickens, etc. Beating on ice isn't exactly a forgiving task, and the cleaver, which is thicker and heavier, did just fine with that.
I think chemistry matters more when you're asking more from the knife, and I think it's a fallacy to say that any modern steel, done well, is anything remotely like a "turd." Cutco/Kabar's 440A does an excellent job with sharpness and edge retention. On those fronts, in my experience, it does at least as well as "better" steels such as S30V and 154CM. The only knife I have that clearly exceeds it on those fronts is M390, heat treated by Peters.
I would never want a 440 sword, of course. There are better steels for that. But there's a tradeoff. There are no steels which give you perfect toughness, sharpness, edge retention, rust prevention, ease of sharpening, etc. Of course there's a reason that Kabar uses 1095CV, which I think have a lot more to do with the affordability and toughness inherent in the steel than in the nebulous "betterness" of the steel over 440A. Better for the intended uses of a field or camp knife? Sure. But by the same token, there's also several reasons why Kabar/Cutco doesn't use 1095CV for its kitchen knives, and I think we can rest assured that if 1095CV were a "better" steel without question, they would.
I'd be surprised to find out that, given Kabar's heat treat in both cases, that a 1095CV chef knife would "blow out of the water" their 440A for the usual purposes of kitchen knives. That's not to say that there aren't better steels for kitchen knife purposes. But I'd also bet that your average person would be hard pressed to tell the difference, which would make that "betterness" rather subjective. I suppose I shouldn't say that steel chemistry doesn't matter. However, I would definitely say that it's fairly close to negligible when compared to the quality of the heat treat. Fub the heat treat, and it doesn't matter how great your steel chemistry is. Similarly, it's dependent upon your desired tasks. Choose the wrong steel for the task, and it's going to be inferior, no matter how great it might be in another setting. That says to me that chemistry is inherently subjective in context of quality, where heat treat is not. YMMV.