A few years back I was helping the stepson of my friend work on his Honda 900. The stepson received a brand new set of plugs, NGK, from his father. The father had acquired them from a friend of his who owned a parts store of some description. They appeared brand new and genuine. We could not get the bike to start at all. So we replaced the new plugs with the old beat up Champions. It fired up no problem. We got curious if the failure to start was because of one or all plugs. So our plan was to replace only on Champion at a time with a NGK. With three Champion and one NGK the engine ran like rubbish. So we swapped that bad NGK out for another NGK. Same result. The remaining two NGK plugs were no different.
I don't think it was an NGK quality problem, as I know people who use NGKs with not issues. I believe they were knock offs from counterfeiters. Understandably retailers look to buy from the least expensive wholesale distributor source. The wholesale distributors purchase from the manufactures, one would hope, so I don't understand how the counterfeits make it into the supply chain. I would hate to think the distributors were knowingly filtering the counterfeits into the system for the sake of profit or that the retailers were knowingly buying them from a questionable sources for the same reason.
I'm sure the problem is not just limited to spark plugs, either.
Steven