A lot of Japanese bikes in the 60's really were pretty disposable. Honda seemed to go for durability and their 4-stroke engines earned a reputation for being bulletproof. But Suzuki, Yamaha, and Kawasaki made a LOT of faster 2-strokes that got them into the market in a big way. You still see lots of old Hondas - 90 Trails buzzing around the woods at the cottage, occasional Dreams and Super Hawks ridden daily - but when did you last spot a running X6 or Avenger?
Chinese bikes are at the same place now, just breaking into the world market with "dubious quality" machinery. The "pocket bikes" have left a bad impression but they are in fact toys, not actual motorcycles.
Don't underestimate Chinese engineering. Japanese products in the 50's were pretty much junk, cheap copies of American and European goods like cameras and watches. In the 60's they learned a LOT, and by the 80's Japanese products were becoming known as the world standard - cameras, watches, bikes, cars, heavy machinery, just about any high profit product.
I think that in 10 years there will be a major Chinese presence in the world bike and car market. I doubt if it will be 20 years before a Chinese vehicle wins "car of the year". Or "bike of the year", if such an award existed in any meaningful way.