I have Buck 110's with S30V and CPM154, and a 112 with D2.
Admittedly the latter two are SK Blades SFO's. Copper & Clad have several SFO's with 5160 carbon steel.
S30V is available on the 110, 112, 113, and 119 (among others) in the Custom Shop. I believe all the Cabala's "Alaskan Guide" knives are S30V. Buck's "Pro" series 110 and 112 have S30V.
I don't follow the "modern" OHO Buck models, so I have no idea which have 420HC; S30-V; S35V or "higher" blades.
The 420HC works just fine for the vast majority of Buck's customers, in town, and/or out in the boonies/sticks, else Buck would use a different standard blade steel.
I know from experience, my 420HC 110 will gut and peel 3 whitetail deer before the edge needs (dry) stropped. (I haven't had a chance to use it for such yet, but I'm guessing my white handle 420C 877 fixed blade will gut and peel just as many.)
I've never felt "under knifed" or wished I had a different knife when out in the boonies/sticks with a 420HC Buck ... or a 1095 carbon steel Old Timer 7OT, Western L66, or Old Hickory, for that matter.
I'm pretty sure they did everything "bushcraft" I needed a knife for, since I haven't lost any parts such as fingers, toes, ears, life, etc. I was born with.
As for "... use 440A seem to be Bargain Basement knives."
My Rough Rider/Rough Ryder, Marbles, "Taylor Schrade" and "Taylor Schrade Hammer Brand" knives with 440A hold an edge just as long, if not a smidgen longer, as my pre-2000 "Schrade +" 7OT; 6OT; circa 1990's Camillus made Remington (not stamped "Schrade +" but nonetheless has stainless steel blades) and 1978-1986 Old Timer 858 (no "OT" in tang stamp") knives do.
I may be mistaken, but I don't
think the Schrade USA family of brand knives were ever/are considered "Bargain Basement" knives, any more than Case was/is. "Budget Friendly", perhaps, but not "Bargain Basement.
Full Disclosure: Case knives were ... "rare" ... at best, in the area of East Central Iowa, where I "grew up". I don't recall any store, other than
maybe Sears, that carried Case.
None of the hardware, tractor/farm supply, or sporting goods stores did, that I remember. Lots of the Schrade brands ,Utica, and Western, but not Case.
I figure to Case, we was just a bunch of "poor" and "stupid" farmers, on the "wrong side of the river", and not worth bothering with.
I don't remember anyone I knew in school, or after, who had a Case pocket or hunting knife. (Starting in 1st or 2nd grade, "everyone" was showing off their knife/knives during recess, and between classes, and in shop classes in Jr. High and High School ... especially those with a Buck 110, and the "rich kids" (actually, they had "rich" parents. The kids themselves might have gotten a bigger allowance, but were as "poor" as the rest of us kids.) that had a Puma lock back, Boker Tree Brand Barlow or stockman, or some other high end German or English brand.
Knives were also shown off at Cub Scout and Boy Scout meetings and camps, and at Sunday School, and Church Luncheons/BB-Q's, of course.

To be honest, I'd not heard of Case prior to joining BF.