Because, for every person like you, there are 10 that would just say "Speaker not work. Must buy new speaker."
Perhaps they would say that, but why on earth would they then buy a speaker from a manufacturer who had screwed them over like that?
In fact if a manufacturer did that to me, I'd tell friends not to buy that brand, and be inclined to tell future generations not to do so also. To this day I don't buy Sony audio equipment because of bad experiences in college.
So I hardly think it likely they would produce something crappy in this way on purpose.