greed and cause they can.. bosch made the 1st 02 sensors but they dont work well in our cars. denso is much cheaper works fine. ngk/ntk makes oem hondas. the 02 sensors r probably more expensive then american made brands because they r so much larger in size. they also last alot longer. u can get 80,000 to 100,000m out of a honda oem one. i just replaced mine for the 1st time may 05, on a 92 accord and i had well over 100,000mi on it. i didnt get a cel i just replaced it anyway. they get lazy after about 80,000mi and get stuck in an open loop pattern.

a friend of mine had a grand am. he replaced his 02 sensor every yr. so he could pass the vet testing. cheap bosch part, but compared to a honda oem and how infrequently u replace it, the honda is the bargain.

some people claim its got a ceramic heater in it but so do the american manufacturers.