My opinion is that it comes down to people not caring as much.

Yeah, that seems obvious, but bear with me here.

Know what the biggest difference there is between knives and guns? It ain't how they do the job as weapons, though that is a big one. It's that guns all work the same, so if you start banning one kind, it ends up applying to far more than anyone that thinks of firearms as an extension of the right to defense, a core human right, is willing to accept.

You ban switchblades, and there's still fixed blades, slipjoints, lockbacks, etc. Nobody has ever tried to make the kind of laws you see around knives in other countries, but if there was an attempt, I don't think there would be as much passion against it as there are with guns because there's just not as much concern about knives as part of the right to defense because guns exist. Range > melee 90% of the time.

Firearms are the gold standard for personal weaponry. So out of the peeps that care about the enumerated right to keep and bear arms simply don't think about knives as much. Same as they don't think about bows, or swords or halberds. They don't care because the fight isn't as relevant to them.

And, on the other side of things, because guns are the gold standard, you don't have as many people targeting knives. There's less to fight against

Now, if guns disappeared, see how quickly crossbows and swords started being the target as people shifted to them instead of guns. That's where the fight would go to. Ban those, and there's going to be steps all the way down until the debate is about how big a rock you are allowed to have.

Also, because of that lack of give-a-shit, knife laws aren't draconian everywhere. There's some states where you can own and carry any knife you want. Others only ban knives that can shoot across the room, or other specific, niche types

Also, I think you're underestimating how easy it is to get a pistol. If you go in without the work done ahead of time, you ain't buying a pistol in half an hour. I don't think even Texas is that loose. Background checks take at least that long. Maybe I'm behind the times om something, but even "shall issue" permit states, you have to count getting the permit in the time factor, imo.