I have a number of knives in the $30-$50 range.
None of them are Spyderco, but that's simply a matter of budget and opportunity. I'll have Spydies soon enough.
Among the brands I do have, which include Kershaw, Buck, Benchmade (NRA Outdoors), Case, and a few others, the only ones I have with uneven grinds or bevels are actually marked with a "factory blemish" code, and I bought them with that imperfection because a) I got 60% off, and b) the blem was either insignificant/unimportant, or it was something I could fix.
As for the rest, the quality of all the knives I have in that range has established a quality expectation that exceeds what the OP depicted.
My "$30 quality" expectation is that grinds and bevels will be even, the blade will be uniformly sharp, there will be no nicks or drags, the pivot will be smooth, the spring will have good snap, the lock will engage positively without allowing any blade play, and the scales and bolsters will not present "ledges" or gaps in the fit.
I have enough "$30" knives meeting that standard such that I would either return or repair something that didn't measure up.
Sure enough, I see marginal quality in some pieces, but I don't buy them.
If I buy one online and it arrives with some kind of flaw -- beyond minor cosmetics -- and if it's something I can't easily remedy, then I return it. I've only had to do that two or three times, and never for a problem with the grind or bevel.
And, yes, some of my "$30" knives are made in China.
I can understand that there will be people who are not bothered by QC lapses, and I'm sure they're comfortable with their choices.
Me? I sort of have this opinion that "QC" is supposed to assure quality, and that accepting a substandard product reinforces the idea that the quality in "QC" doesn't have to be particularly tight, because, hey -- it's no big deal, right?
If I run a factory that makes knives, and I've got knives hitting the streets that have quality standards issues, I don't want to find out about it when people stop buying my product. I want to know about it while I can still correct my production.
Quality is my front line PR. It's my public's first impression. It's what generates repeat business.
Lack of quality says I don't care, and the customer is not as important as my making my quotas.
If this is *my* business, I damn well *do* care, and I want precise and timely feedback from my customers.
And, since that's how I would run *my* business, I expect that the people making the knives I buy have that same attitude and want that same feedback. And so I don't just shrug off quality failures.
I figure that if I help them maintain quality, the improved product will keep other customers happy and keep the manufacturer in business, and they will still be there when I want to buy my next knife.
But that's just me. I could be wrong.