Odd placement of this thread, would be better in the Spyderco forum or the General discussion forum.
Anyway...
Spyderco knives are popular because they are designed with function in mind, and aesthetics second. They're made to cut, not look pretty, which is why most people find them so fugly. They're typically very well made, and they won't fail you. Sure some lemons slip through once in a while, but those are few and far between.
Not all Spyderco are made in Japan, many are made in the US. They also have facilities in Taiwan, Italy, and in the past, Germany and several others.
Additionally, the biggest reason for Spyderco's popularity is that the knives are relatively inexpensive. Not sure what you mean by high dollar, but the most popular Spydercos, the Delicas/Enduras are only around $50 and are unquestionably the best bang for the buck in that price range. I don't consider that high dollar at all.
With the exception of some of the new very high end specialized knives(T-Mag, Pikal) most Spydercos are below $100 street price.
All that aside, to answer your original question regarding the Japanese made knives...
Yes they are worth the "high" price, despite that they're not made in the US. I've said it in the past, and I'll say it again, Seki made Spyders have superior fit and finish compared to the US made. That's not to say the US made knives are bad, it's just the Japanese pay more attention to detail.
I think you're confusing "Made in Japan" with "Made in China." There's a huge difference in quality between the two.